For individuals living in economically developed environments, rates of non-communicable diseases associated with overnutrition, such as type 2 diabetes mellitus and many forms of heart disease, are serious concerns(1). In addition to the decreasing quality of life(Reference Saboya, Bodanese and Zimmermann2) and potential lifespan(Reference Benjamin, Muntner and Alonso3), these diseases collectively contribute to extreme economic burdens to the individual and society as a whole(Reference Benjamin, Muntner and Alonso3). Nutrition and physical activity are each independent risk factors for the development of cardiometabolic diseases and associated mortality(Reference Carnethon4). Despite knowledge of the benefits of improved dietary intake and physical activity, three quarters of Americans follow an eating pattern low in fruits and vegetables(5) and only half of adults meet the minimum aerobic physical activity recommendations(6).
Population-level improvement of nutrition and physical activity behaviours may decrease development and progression of cardiometabolic disease. This may, in turn, result in improved quality of life and a decreased burden of personal and national health care costs. To improve health behaviours on a population level, evidence-based guidance is needed to inform nutrition and physical activity practitioners working with clients in the community, workplace or out-patient settings.
The aim of a scoping review is to map the availability of research, both systematic reviews (SR) and guidelines as well as controlled trials, in areas of interest to determine where resources are available to guide practice, and where evidence is still needed(Reference Peters, Godfrey, McInerney, Aromataris and Munn7). Additionally, a scoping review can identify which current topics still require SR and evidence-based practice guidelines to inform practitioners working with individuals who are healthy or who have cardiometabolic risk factors. This scoping review was conducted to determine if current evidence was available on relevant nutrition and physical activity interventions for the general population. Specific areas of interest that require clarification or are important to policy or practice were identified by practitioners currently working with clients in the field and are addressed in the individual research questions.
The objective of this scoping review is to address the overarching research question: In adults in the ‘general population’, including non-athletes or recreational athletes with or without cardiometabolic risk factors, what is the extent, range and nature of literature examining interventions to improve or maintain nutrition and physical activity and related outcomes? Specific research questions examined availability of research describing:
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Question 1 (Q1). Individual-level nutrition and physical activity counseling or coaching provided by a dietitian/nutritionist and/or exercise practitioner;
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Question 2 (Q2). Mobile applications (apps) and/or wearable technology;
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Question 3 (Q3). Nutritional ergogenic aids of interest.
Methods
This scoping review was conducted with the framework introduced by Arksey and O’Malley(Reference Arksey and O’Malley8) and developed by Levac et al. (Reference Levac, Colquhoun and Brien9) and the Joanna Briggs Institute(Reference Peters, Godfrey, McInerney, Aromataris and Munn7). This scoping review was registered on Open Science Framework (osf.io/pc6sy)(Reference Rozga10) and adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist for scoping reviews(Reference Tricco, Lillie and Zarin11).
Eligibility criteria
A full description of eligibility criteria can be found in Table 1. The target population for this scoping review was adults in the ‘general’ population living in economically developed countries, such as the USA(12). The authors recognised that currently, a ‘general’ population does not imply a ‘healthy’ population, since cardiometabolic risk factors may exist in a majority of adults. Thus, this scoping review included individuals with no risk, risk for and diagnosed with cardiometabolic disease.
Eligibility criteria for studies including in scoping review examining effect of nutrition and physical activity interventions in the general population
BCAA, branched chain amino acid; BMD, bone mineral density; BP, blood pressure; COPD, chronic obstructive pulmonary disease; CRP, C-reactive protein; FFM, fat-free mass; FM, fat mass; IBD, irritable bowel disease; PCOS, polycystic ovarian syndrome; Q1, Question 1; Q2, Question 2; Q3, Question 3; RCT, randomised controlled trial.
Three areas of nutrition and physical activity interventions were explored in this scoping review: (1) counseling or coaching, (2) mobile applications and (3) nutritional ergogenic aids. Q1 examined the efficacy of nutrition and physical activity counseling or coaching provided by a dietitian/nutritionist and/or exercise practitioner (see Table 1 for specific criteria). For Q1 inclusion, study participants must have received at least some individual-level counseling in nutrition and/or physical activity. Q2 explored the efficacy of mobile apps and other wearable technology in nutrition and physical activity interventions. For these two questions, studies were required to be controlled trials, either randomised controlled trial (RCT) or non-RCT. Q3 examined efficacy nutritional ergogenic aids deemed as commonly used in the ‘general’ population (Table 1). For Q3 only (nutritional ergogenic aids), studies were required to be placebo-controlled RCT. Additionally, for Q3, studies were limited to those reporting anthropometric, body composition and performance outcomes. For all questions, primary studies were included if they were published in 2005 or later to balance a wide breadth of evidence with relevancy of interventions to the current population. SR answering at least one of the research questions were included if published in 2015 or later, since SR published earlier than 2015 may require updated information. Included studies were limited to those published in the English language due to resource constraints.
Search plan
Search strategies were written by an Information Specialist for the following databases via the Ebsco interface: Medline Complete, CINAHL Complete, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials and Food Science Source. Searches were run on 4 and 5 May 2020. Two methodological filters were used, one for SR and meta-analyses, and another observational and other study designs. Results were limited to English language and publication year 2005 forward. Results were managed and deduplicated in Endnote Software. A sample search strategy can be found in online supplementary material, Supplemental 1.
Study selection and data extraction
Article screening was conducted in two phases. In the first phase, each title/abstract was reviewed by at least one reviewer (M.R.) and 22·4 % of title/abstracts were reviewed by a second reviewer (A.Y.) using Rayyan screening software(Reference Ouzzani, Hammady and Fedorowicz13). Any discrepancies between authors were discussed until consensus was reached. Communication between reviewers throughout the screening process solidified eligibility criteria. Included title/abstracts moved to the second phase of the full-text review. Prior to the full-text review, authors collaborated to create a template allowing for standardised data extraction and coding, including but not limited to: study design, sample size, population age group, activity level, health status, research question addressed including details specific to the research question (e.g., practitioner delivering the intervention for Q1) and outcomes reported. One of two reviewers (M.R. or A.Y.) reviewed the full text, determined eligibility and extracted data for included articles. The second reviewer confirmed reason for exclusion or checked accuracy of extracted data. Relevant SR were searched for eligible articles that may have been missed by the databases search.
Synthesis of results
The study selection process was documented using a PRISMA flow chart(Reference Moher, Liberati and Tetzlaff14). Data were analysed according to the specific research question addressed and types of studies included. A bubble chart was created to demonstrate publication trends according to the sub-question addressed. For each of the three questions, a heat map was created to demonstrate density of interventions according to the population, type of intervention and/or outcomes reported. As is customary for scoping reviews, critical appraisal of study quality and meta-analyses were not conducted.
Results
The databases and hand searches identified 19 474 unique articles. Following title/abstract screening, 657 full texts were reviewed, and 170 articles answering at least one of the research questions were included in this scoping review (Fig. 1). Eighty-three of the eighty-nine articles not meeting population criteria were specifically excluded for including participants with BMI ≥ 40 kg/m2. Of the articles included, one was an evidence-based practice guideline(Reference Lennon, DellaValle and Rodder15), thirty were SR(Reference Abdelhamid, Hooper and Sivakaran16–Reference Xu, Tan and Zhang45), 134 were RCT(Reference Adachi, Yamaoka and Watanabe46–Reference Zuniga, Housh and Camic179) and five were non-RCT(Reference Haruyama, Muto and Nakade180–Reference Wilson, Castro Sweet and Edge184). Forty-eight of the articles were included for Q1 (counseling and coaching), thirty-seven articles were included for Q2 (mobile apps and wearables) and eighty-seven articles were included for Q3 (nutritional ergogenic aids of interest). While the rate of publication was relatively constant over the study period for articles examining nutrition and physical activity counseling and coaching (Q1), the number of primary research articles (not including SR) examining the effects of nutrition and physical activity mobile apps and/or wearables as well as nutritional ergogenic aids of interest grew considerably from approximately 2015–2020 (Fig. 2).
PRISMA flow chart(Reference Moher, Liberati and Tetzlaff14) describing the study inclusion process for a scoping review examining the availability of studies with interventions including both nutrition and physical activity in the general population
Bubble chart of publication trends in primary research articles published from 2005 to 2020 according to the research question addressed
Question 1: Individual-level nutrition and physical activity counseling or coaching provided by a dietitian/nutritionist or exercise practitioner
Forty-eight articles(Reference Lennon, DellaValle and Rodder15,Reference Maciejewski, Shepherd-Banigan and Raffa32,Reference Adachi, Yamaoka and Watanabe46,Reference Admiraal, Vlaar and Nierkens47,Reference Allman-Farinelli, Partridge and McGeechan49,Reference Arciero, Gentile and Martin-Pressman51,Reference Aro, Kauppinen and Kivinen52,Reference Bennett, Herring and Puleo56,Reference Colleluori, Napoli and Phadnis69,Reference Corpeleijn, Feskens and Jansen74,Reference Corpeleijn, Feskens and Jansen76,Reference Dale, Mann and McAuley78,Reference Droste, Iliescu and Vaillant83,Reference Fernández-García, Martínez-Sánchez and Bernal-López89–Reference Foster-Schubert, Alfano and Duggan91,Reference Hageman, Pullen and Hertzog101–Reference Haste, Adamson and McColl104,Reference Hollis, Williams and Morgan108,Reference Hurkmans, Matthys and Bogaerts109,Reference Imayama, Alfano and Kong111,Reference Kuller, Pettee Gabriel and Kinzel120,Reference Lammes, Rydwik and Akner121,Reference Magriplis, Sialvera and Papadopoulou128,Reference Maruyama, Kimura and Okumura130,Reference Nakade, Aiba and Suda133,Reference Partridge, McGeechan and Hebden138,Reference Partridge, McGeechan and Bauman139,Reference Puhkala, Kukkonen-Harjula and Aittasalo142,Reference Ross and Wing147–Reference Roumen, Feskens and Corpeleijn151,Reference Salas-Salvadó, Díaz-López and Ruiz-Canela154,Reference Schrader, Panek and Temple157,Reference Sialvera, Papadopoulou and Efstathiou160–Reference Smith, Bracha and Svendsen162,Reference Tanaka, Murakami and Aiba169,Reference van Wier, Ariëns and Dekkers171,Reference van Dongen, Haveman-Nies and Doets172,Reference Williams, Hollis and Collins177,Reference Haruyama, Muto and Nakade180,Reference Miller, Martz and Stoner182,Reference Wilson, Castro Sweet and Edge184) representing thirty-eight studies met inclusion criteria and examined the effect of nutrition and physical activity counseling or coaching from a dietitian/nutritionist or exercise practitioner, including one evidence-based practice guideline, one SR, thirty-three RCT and three NRCT. The populations, intervention providers and reported outcomes are shown in Table 2. Of the thirty-three primary studies, twenty-eight targeted participants with cardiometabolic risk factors, primarily individuals with overweight or obesity. Five studies met eligibility criteria that targeted participants with cardiometabolic disease (type 2 diabetes mellitus and CVD)(Reference Adachi, Yamaoka and Watanabe46,Reference Droste, Iliescu and Vaillant83,Reference Haste, Adamson and McColl104,Reference Ross and Wing147,Reference Simpson, Pajewski and Nicklas161) , and another five studies included participants with another morbidity, sarcopenia(Reference Colleluori, Napoli and Phadnis69,Reference Lammes, Rydwik and Akner121,Reference Rydwik, Lammes and Frändin149,Reference van Dongen, Haveman-Nies and Doets172) and non-severe anxiety and depression(Reference Forsyth, Deane and Williams90) in four and one study, respectively. Two trials (entitled the TXT2Bfit and 40 something trials) included participants who were both at cardiometabolic risk and who did not have cardiometabolic risk factors but were at risk of weight gain(Reference Allman-Farinelli, Partridge and McGeechan49,Reference Partridge, McGeechan and Hebden138,Reference Partridge, McGeechan and Bauman139) or were perimenopausal women(Reference Hollis, Williams and Morgan108,Reference Williams, Hollis and Collins177) . Sample sizes ranged from 28 to 11 827 participants and study durations ranged from 4 weeks to 8 years. Nutrition and physical activity counseling or coaching was provided by a dietitian/nutritionist only in fifteen studies(Reference Lennon, DellaValle and Rodder15,Reference Maciejewski, Shepherd-Banigan and Raffa32,Reference Adachi, Yamaoka and Watanabe46,Reference Admiraal, Vlaar and Nierkens47,Reference Aro, Kauppinen and Kivinen52,Reference Droste, Iliescu and Vaillant83,Reference Fernández-García, Martínez-Sánchez and Bernal-López89,Reference Hageman, Pullen and Hertzog101,Reference Magriplis, Sialvera and Papadopoulou128,Reference Partridge, McGeechan and Bauman139,Reference Ross and Wing147,Reference Roumen, Feskens and Corpeleijn151,Reference Sialvera, Papadopoulou and Efstathiou160,Reference Smith, Bracha and Svendsen162,Reference Miller, Martz and Stoner182) , an exercise practitioner only in two studies(Reference Bennett, Herring and Puleo56,Reference Wilson, Castro Sweet and Edge184) and both a dietitian/nutritionist and exercise practitioner in twenty-one studies(Reference Arciero, Gentile and Martin-Pressman51,Reference Colleluori, Napoli and Phadnis69,Reference Dale, Mann and McAuley78,Reference Forsyth, Deane and Williams90,Reference Foster-Schubert, Alfano and Duggan91,Reference Hardcastle, Taylor and Bailey102,Reference Hardcastle, Taylor and Bailey103,Reference Hollis, Williams and Morgan108,Reference Imayama, Alfano and Kong111,Reference Kuller, Pettee Gabriel and Kinzel120,Reference Lammes, Rydwik and Akner121,Reference Maruyama, Kimura and Okumura130,Reference Puhkala, Kukkonen-Harjula and Aittasalo142,Reference Rydwik, Lammes and Frändin149,Reference Simpson, Pajewski and Nicklas161,Reference Tanaka, Murakami and Aiba169,Reference van Wier, Ariëns and Dekkers171,Reference van Dongen, Haveman-Nies and Doets172,Reference Haruyama, Muto and Nakade180) . The greatest density of studies examined participants with cardiometabolic risk factors and interventions delivered by a dietitian/nutritionist and exercise practitioner or a dietitian/nutritionist only, and reporting anthropometric, glucose homoeostasis, blood pressure, lipid profile, dietary intake and physical activity outcomes. The one included SR reported the outcome of weight change(Reference Maciejewski, Shepherd-Banigan and Raffa32). Exercise practitioners providing interventions were heterogeneous and included physiotherapists (n 4), exercise physiologists (n 7), physical trainer (n 1), physical activity ‘specialist’ or ‘coach’ (n 3), exercise or physical activity instructors (n 3) and health coaches (n 2) among others.
Primary studies examining the effect of nutrition and physical activity counseling/coaching according to the provider of intervention and outcomes reported (n 36 studies)
Red colour = >5 studies, light orange colour = 1–5 studies, light yellow colour = no available studies.
* Includes cardiovascular risk, type 2 diabetes mellitus risk, overweight and obesity and metabolic syndrome.
† Simpson et al. (Reference Simpson, McNamara and Shaw191) reported frailty index, which is not reported in the table.
‡ Includes osteopenia, osteoporosis, osteoarthritic and bone mineral density/content.
Question 2: Nutrition and physical activity mobile apps and/or wearable technology
A total of thirty-six articles(Reference Dounavi and Tsoumani18,Reference Cheatham, Stull and Fantigrassi19,Reference Kim and Seo21,Reference Flores Mateo, Granado-Font and Ferré-Grau22,Reference Lunde, Nilsson and Bergland30,Reference Milne-Ives, Lam and De Cock34,Reference Puigdomenech Puig, Robles and Saigí-Rubió35,Reference Schoeppe, Alley and Van Lippevelde37,Reference Sypes, Newton and Lewis40,Reference Veazie, Winchell and Gilbert42–Reference Wu, Guo and Zhang44,Reference Aktas, Mähler and Hamm48,Reference Byrne, Meerkin and Laukkanen59,Reference Day, Jahnke and Haddock80,Reference Epton, Norman and Dadzie87,Reference Garcia-Ortiz, Recio-Rodriguez and Agudo-Conde94,Reference Gomez-Marcos, Patino-Alonso and Recio-Rodriguez95,Reference Gonzalez-Sanchez, Recio-Rodriguez and Fernandez-delRio97,Reference Greene, Sacks and Piniewski100,Reference Hebden, Cook and van der Ploeg106,Reference Hurkmans, Matthys and Bogaerts109,Reference Jakicic, Davis and Rogers113,Reference Kruger, Brennan and Strong119,Reference Lara, O’Brien and Godfrey123,Reference Lisón, Palomar and Mensorio126,Reference Martin, Miller and Thomas129,Reference Pellegrini, Verba and Otto140,Reference Polzien, Jakicic and Tate141,Reference Recio-Rodriguez, Agudo-Conde and Martin-Cantera143–Reference Recio-Rodríguez, Rodriguez-Sanchez and Martin-Cantera145,Reference Ross and Wing147,Reference Wayne, Perez and Kaplan176,Reference Mailey, Irwin and Joyce181,Reference West, Monroe and Turner-McGrievy183) representing thirty studies were included for Q2, which examined the effects of nutrition and physical activity mobile apps and/or wearables. Studies included were SR (n 12), RCT (n 16) and non-RCT (n 2). The populations, study designs and reported outcomes are shown in Table 3. Ten studies included participants who were healthy(Reference Flores Mateo, Granado-Font and Ferré-Grau22,Reference Milne-Ives, Lam and De Cock34,Reference Schoeppe, Alley and Van Lippevelde37,Reference Sypes, Newton and Lewis40,Reference Day, Jahnke and Haddock80,Reference Epton, Norman and Dadzie87,Reference Garcia-Ortiz, Recio-Rodriguez and Agudo-Conde94,Reference Gonzalez-Sanchez, Recio-Rodriguez and Fernandez-delRio97,Reference Lara, O’Brien and Godfrey123,Reference Mailey, Irwin and Joyce181) and twenty-one studies included participants with cardiometabolic risk factors(Reference Dounavi and Tsoumani18,Reference Cheatham, Stull and Fantigrassi19,Reference Kim and Seo21,Reference Flores Mateo, Granado-Font and Ferré-Grau22,Reference Milne-Ives, Lam and De Cock34,Reference Puigdomenech Puig, Robles and Saigí-Rubió35,Reference Sypes, Newton and Lewis40,Reference Aktas, Mähler and Hamm48,Reference Byrne, Meerkin and Laukkanen59,Reference Garcia-Ortiz, Recio-Rodriguez and Agudo-Conde94,Reference Gomez-Marcos, Patino-Alonso and Recio-Rodriguez95,Reference Gonzalez-Sanchez, Recio-Rodriguez and Fernandez-delRio97,Reference Greene, Sacks and Piniewski100,Reference Hebden, Cook and van der Ploeg106,Reference Hurkmans, Matthys and Bogaerts109,Reference Jakicic, Davis and Rogers113,Reference Lisón, Palomar and Mensorio126,Reference Martin, Miller and Thomas129,Reference Pellegrini, Verba and Otto140,Reference Polzien, Jakicic and Tate141,Reference West, Monroe and Turner-McGrievy183) . Only six studies meeting eligibility criteria included participants with cardiometabolic diseases (type 2 diabetes mellitus and CVD)(Reference Lunde, Nilsson and Bergland30,Reference Veazie, Winchell and Gilbert42–Reference Wu, Guo and Zhang44,Reference Ross and Wing147,Reference Wayne, Perez and Kaplan176) . Five studies included both participants who were both healthy and those who had cardiometabolic risk factors(Reference Flores Mateo, Granado-Font and Ferré-Grau22,Reference Milne-Ives, Lam and De Cock34,Reference Sypes, Newton and Lewis40,Reference Garcia-Ortiz, Recio-Rodriguez and Agudo-Conde94,Reference Gonzalez-Sanchez, Recio-Rodriguez and Fernandez-delRio97) . Sample sizes ranged from 34 to 1007 participants and study durations ranged from 8 to 32 weeks. There were no patient-centred health outcomes reported for studies with participants who were healthy or at cardiometabolic risk. The greatest density of primary studies and SR examined individuals with cardiometabolic risk factors and reported anthropometric, dietary intake and physical activity outcomes. Six SR addressed the efficacy of mobile apps and wearables for nutrition and physical activity and were published from 2019 until the search date of 4 May 2020(Reference Dounavi and Tsoumani18,Reference Kim and Seo21,Reference Milne-Ives, Lam and De Cock34,Reference Puigdomenech Puig, Robles and Saigí-Rubió35,Reference Sypes, Newton and Lewis40,Reference Wu, Guo and Zhang44) .
Heat map of controlled trials examining the effect of mobile apps and/or wearable devices for nutrition and physical activity according to the target populations and reported outcomes (n 30 studies)
Red colour = >5 studies, light red colour = 1–5 studies, blue colour = no available studies.
* Includes CVD risk, type 2 diabetes mellitus risk, overweight and obesity and metabolic syndrome.
Question 3: Nutritional ergogenic aids
A total of eighty-seven articles, including seventeen SR(Reference Abdelhamid, Hooper and Sivakaran16,Reference Beaudart, Rabenda and Simmons17,Reference Chilibeck, Kaviani and Candow20,Reference Forbes, Chilibeck and Candow23–Reference Lanhers, Pereira and Naughton29,Reference Zheng-Tao, Zhang and Zhu31,Reference Martínez-Arnau, Fonfría-Vivas and Cauli33,Reference Raya-González, Rendo-Urteaga and Domínguez36,Reference Southward, Rutherfurd-Markwick and Ali38,Reference Stares and Bains39,Reference Valenzuela, Morales and Castillo-García41,Reference Xu, Tan and Zhang45) and seventy placebo-controlled RCT(Reference Andersson-Hall, Pettersson and Edin50,Reference Ballard, Melby and Camus53–Reference Bemben, Witten and Carter55,Reference Bernat, Candow and Gryzb57,Reference Black, Waddell and Gonglach58,Reference Burke, Candow and Chilibeck60–Reference Church, Hoffman and LaMonica68,Reference Collier, Hardy and Millard-Stafford70–Reference Cornish, Myrie and Bugera73,Reference Cooke, Brabham and Buford75,Reference Da Boit, Sibson and Sivasubramaniam77,Reference Dalton, Sowinski and Grubic79,Reference Demura, Yamada and Terasawa81,Reference DiLorenzo, Drager and Rankin82,Reference Del Coso, Salinero and González-Millán84–Reference Eliot, Knehans and Bemben86,Reference Ferguson and Syrotuik88,Reference Fouré, Nosaka and Gastaldi92,Reference Funderburk, Beretich and Chen93,Reference Gonglach, Ade and Bemben96,Reference Graef, Smith and Kendall98,Reference Gray, Chappell and Jenkinson99,Reference Herda, Beck and Ryan105,Reference Hill, Buckley and Murphy107,Reference Hutchins-Wiese, Kleppinger and Annis110,Reference Jakeman, Lambrick and Wooley112,Reference James and Kjerulf Greer114–Reference Koenig, Benardot and Cody118,Reference Lane and Byrd122,Reference Lara, Ruiz-Moreno and Salinero124,Reference Lembke, Capodice and Hebert125,Reference Logan and Spriet127,Reference Lane, Byrd and Bell131,Reference Mobley, Haun and Roberson132,Reference Nicks and Martin134–Reference O’Malley, Myette-Cote and Durrer137,Reference Reule, Scholz and Schoen146,Reference Ruíz-Moreno, Lara and Brito de Souza152,Reference Sabol, Grgic and Mikulic153,Reference Salinero, Lara and Ruiz-Vicente155–Reference Schrader, Panek and Temple157,Reference Shimomura, Inaguma and Watanabe159,Reference Smith, Julliand and Reeds163–Reference Tallis and Yavuz168,Reference Tinsley, Gann and Huber170,Reference Verhoeven, Vanschoonbeek and Verdijk173,Reference Wallman, Goh and Guelfi175,Reference Zdzieblik, Oesser and Baumstark178,Reference Zuniga, Housh and Camic179) , examined the effect of nutritional ergogenic aids on physical activity, anthropometric and body composition outcomes. Sample sizes ranged from 10 to 118 participants and study durations ranged from 1 d to 1 year. Nearly all included articles focused on one dietary supplement of interest (branched chain amino acids, caffeine, carbohydrate replacement, collagen, creatine, exogenous ketones, multivitamins and n-3 fatty acids), with the exception of one RCT that assessed both creatine and carbohydrate supplementation(Reference Koenig, Benardot and Cody118) and one SR that assessed both creatine and the branched chain amino acid leucine(Reference Beaudart, Rabenda and Simmons17).The most frequently examined ergogenic aid was creatine (n 6 SR(Reference Beaudart, Rabenda and Simmons17,Reference Chilibeck, Kaviani and Candow20,Reference Forbes, Chilibeck and Candow23,Reference Lanhers, Pereira and Naughton28,Reference Lanhers, Pereira and Naughton29,Reference Stares and Bains39) and 22 RCT(Reference Bemben, Witten and Carter55,Reference Bernat, Candow and Gryzb57,Reference Burke, Candow and Chilibeck60–Reference Chilibeck, Candow and Landeryou67,Reference Cornish, Candow and Jantz72,Reference Cooke, Brabham and Buford75,Reference Dalton, Sowinski and Grubic79,Reference Eliot, Knehans and Bemben86,Reference Ferguson and Syrotuik88,Reference Graef, Smith and Kendall98,Reference Herda, Beck and Ryan105,Reference Johannsmeyer, Candow and Brahms117,Reference Koenig, Benardot and Cody118,Reference Spillane, Schoch and Cooke164,Reference Stout, Sue Graves and Cramer165,Reference Zuniga, Housh and Camic179) ), followed by caffeine (n 5 SR(Reference Grgic25–Reference Grgic, Grgic and Pickering27,Reference Raya-González, Rendo-Urteaga and Domínguez36,Reference Southward, Rutherfurd-Markwick and Ali38) and 20 RCT(Reference Bazzucchi, Felici and Montini54,Reference Black, Waddell and Gonglach58,Reference Church, Hoffman and LaMonica68,Reference Collier, Hardy and Millard-Stafford70,Reference Demura, Yamada and Terasawa81,Reference Del Coso, Salinero and González-Millán84,Reference Gonglach, Ade and Bemben96,Reference Lane and Byrd122,Reference Lara, Ruiz-Moreno and Salinero124,Reference Lane, Byrd and Bell131,Reference Nicks and Martin134,Reference Olcina, Timón and Muñoz136,Reference Ruíz-Moreno, Lara and Brito de Souza152,Reference Sabol, Grgic and Mikulic153,Reference Salinero, Lara and Ruiz-Vicente155,Reference Schrader, Panek and Temple157,Reference Tallis, Duncan and Wright166–Reference Tallis and Yavuz168,Reference Wallman, Goh and Guelfi175) ). There were no SR available for carbohydrate replacement (n 4 RCT(Reference Andersson-Hall, Pettersson and Edin50,Reference Ballard, Melby and Camus53,Reference Dupuy and Tremblay85,Reference Koenig, Benardot and Cody118) ) or collagen (n 2 RCT(Reference Jendricke, Centner and Zdzieblik116,Reference Zdzieblik, Oesser and Baumstark178) ) in non- or recreational athletes. There were four SR(Reference Beaudart, Rabenda and Simmons17,Reference Fouré and Bendahan24,Reference Martínez-Arnau, Fonfría-Vivas and Cauli33,Reference Xu, Tan and Zhang45) and six RCT(Reference Fouré, Nosaka and Gastaldi92,Reference Funderburk, Beretich and Chen93,Reference Mobley, Haun and Roberson132,Reference Reule, Scholz and Schoen146,Reference Shimomura, Inaguma and Watanabe159,Reference Verhoeven, Vanschoonbeek and Verdijk173) that focused on branched chain amino acids (primarily leucine); one SR(Reference Valenzuela, Morales and Castillo-García41) and two RCT(Reference James and Kjerulf Greer114,Reference O’Malley, Myette-Cote and Durrer137) examined the effect of exogenous ketones; and two SR(Reference Abdelhamid, Hooper and Sivakaran16,Reference Zheng-Tao, Zhang and Zhu31) and fifteen RCT(Reference Corder, Newsham and McDaniel71,Reference Cornish, Myrie and Bugera73,Reference Da Boit, Sibson and Sivasubramaniam77,Reference DiLorenzo, Drager and Rankin82,Reference Gray, Chappell and Jenkinson99,Reference Hill, Buckley and Murphy107,Reference Hutchins-Wiese, Kleppinger and Annis110,Reference Jakeman, Lambrick and Wooley112,Reference Jannas-Vela, Roke and Boville115,Reference Lembke, Capodice and Hebert125,Reference Logan and Spriet127,Reference Ochi, Tsuchiya and Yanagimoto135,Reference Schattin, Baier and Mai156,Reference Smith, Julliand and Reeds163,Reference Tinsley, Gann and Huber170) examined the effect of n-3 fatty acid supplementation. There were no placebo-controlled RCT or SR identified that evaluated the effect of multivitamins in the population of interest. Table 4 displays a heat map of the distribution of outcomes assessed in RCT and SR for each ergogenic aid of interest. Of the seventy included RCT, only two did not assess exercise/performance outcomes; one examined creatine(Reference Eliot, Knehans and Bemben86) and that the other on n-3 fatty acids(Reference Hill, Buckley and Murphy107). None of the included RCT measured physical activity outcomes using metabolic equivalents of task and only two of the SRs assessed metabolic equivalents of task as an outcome measure of interest(Reference Zheng-Tao, Zhang and Zhu31,Reference Martínez-Arnau, Fonfría-Vivas and Cauli33) . For the nutritional ergogenic aids caffeine, creatine and n-3 fatty acid supplements, SR published in 2019 and 2020 were available (Fig. 3).
Heat map of placebo-controlled randomised controlled trials and systematic reviews examining the effect of ergogenic aids according to the supplement and reported outcomes (n 87 studies)
Red colour = >5 studies identified; orange colour = 1–5 studies identified; light yellow colour = no studies identified.
Bubble chart of placebo-controlled randomised controlled trials and systematic reviews published by year and by ergogenic aid. The bubble size is proportional to the number of studies published in the year for each ergogenic aid. 
, RCT; 
, SR
Discussion
This scoping review included 170 primary and secondary research articles that examined the effect of nutrition and physical activity interventions in individuals who were non-athletes or recreational athletes and who were healthy or had cardiometabolic risk. While primary research has been consistently available on the effect of individual-level nutrition and physical activity counseling or coaching from a dietitian or exercise practitioner, there has been little synthesis of these data in the 5 years of SR (2015–2020) examined. SR published prior to 2015 may be valuable for practice(Reference Johns, Hartmann-Boyce and Jebb185), but practitioners should be mindful that new evidence may shift conclusions. Additionally, newer SR may be more relevant to current circumstances (e.g., need for remote coaching/counseling during the COVID-19 pandemic). Mobile applications designed to improve nutrition and physical activity had been addressed in several primary studies over the past 5 years; these studies have been well-represented in SR. Regarding nutritional ergogenic aids of interest, recent SR were available for the supplements with relatively high publication activity (caffeine, creatine and n-3 fatty acids), particularly for the outcome of exercise performance. However, other commonly used ergogenic aids have relatively few SR available to guide practice.
Question 1: Individual-level nutrition and physical activity counseling or coaching provided by a dietitian/nutritionist or exercise practitioner
Prior education, experience, methodologies and assessment techniques can differ significantly among practitioners delivering nutrition and physical activity interventions. Studies in this scoping review included a range of practitioners providing nutrition and exercise counseling or coaching, particularly among exercise practitioners. In addition, state and federal regulations for scope of practice vary, potentially allowing less-than-qualified practitioners to provide nutrition and/or physical activity guidance. While decreasing standards may increase accessibility, there is also risk of lower quality care and, therefore, lower intervention efficacy when care is provided by non-qualified practitioners. Examining how provider qualifications impact outcomes may inform scope of practice for both dietitian/nutritionists and exercise practitioners working with different sub-groups of the ‘general’ population. For example, those with cardiometabolic disease or risk factors for cardiometabolic disease may require medical nutrition therapy provided by a Registered Dietitian, while direct coaching from an exercise practitioner may be required for individuals who are sedentary and/or have little exercise history. There were no studies included that investigated the effect on an intervention in individuals that had no cardiometabolic risk factors or disease. Most available primary studies investigated individuals with cardiometabolic risk, such as those with overweight or obesity, and investigated intermediate outcomes such as anthropometric measures, blood pressure, lab values and behavioural outcomes, which would indicate the prevention of progression towards cardiometabolic disease. A SR on the effects of nutrition and physical activity interventions in individuals with no risk factors may yield few results. However, signs and symptoms of cardiometabolic risk, such as incidence of overweight and pre-diabetic levels of fasting blood glucose, may overlap. Thus, in SR, it may be beneficial to group individuals with cardiometabolic risk factors, but without diagnosed disease.
The United States Preventative Task Force recently conducted a SR on the effect of behaviour counseling for nutrition and physical activity for individuals with cardiovascular risk on CVD outcomes(Reference O’Connor, Evans and Rushkin186). The current working version describes a beneficial effect on cardiovascular events, adiposity-related outcomes and many other health outcomes(187). The current scoping review focused on interventions delivered by nutrition and/or exercise practitioners specifically and included a broader range of participants. SR examining differences in outcomes according to the practitioner delivering the intervention can inform health care providers of the most effective methods to improve dietary intake and physical activity behaviours.
Question 2: Nutrition and physical activity mobile apps and wearable technology
Most studies examining the effectiveness of mobile apps in improving cardiometabolic risk factors have reported outcomes relating to energy intake, storage and output (dietary intake, anthropometrics and physical activity, respectively, Table 3). Fewer studies have assessed the influence of apps on treating those with cardiometabolic conditions, such as type 2 diabetes mellitus and CVD. This discrepancy may be intentional to curtail liability from self-diagnosis or self-treatment based on data or guidance from the app itself and in the absence of a qualified nutrition or exercise practitioner. However, several SR targeting individuals who are healthy or who have cardiometabolic risk factors are available to guide practitioners on the efficacy of utilising mobile apps with clients(Reference Dounavi and Tsoumani18,Reference Cheatham, Stull and Fantigrassi19,Reference Kim and Seo21,Reference Flores Mateo, Granado-Font and Ferré-Grau22,Reference Lunde, Nilsson and Bergland30,Reference Milne-Ives, Lam and De Cock34,Reference Puigdomenech Puig, Robles and Saigí-Rubió35,Reference Schoeppe, Alley and Van Lippevelde37,Reference Sypes, Newton and Lewis40,Reference Veazie, Winchell and Gilbert42–Reference Wu, Guo and Zhang44) . Studies investigating individuals without cardiometabolic disease may offer valuable insights in broad-scale interventions implemented prior to individuals experiencing adverse symptoms of cardiometabolic risk and disease. Like the question investigating nutrition and physical activity counseling or coaching (Question 1), the highest density of evidence available examined individuals with cardiometabolic risk factors. These interventions most frequently reported outcomes that would indicate improved behaviours and intermediate outcomes that may indicate the prevention of cardiometabolic disease.
Use of and technology related to smartphone applications and forms of telehealth will likely continue to advance(Reference Rozga, Handu and Kelley188,189) , particularly in light of the need for remote interventions due to the COVID-19 pandemic. Thus, the number of available studies in this domain may require further synthesis including examination of effective app components, differences between apps that simply track behaviour or biomarker data compared with those which provide recommendations and differences in apps developed directly by medical providers (hospitals, insurance providers) v. third-party companies.
Question 3: Nutritional ergogenic aids
Participants were healthy individuals without cardiometabolic risk factors in all except two studies investigating the effect of ergogenic aids(Reference Hill, Buckley and Murphy107,Reference Zdzieblik, Oesser and Baumstark178) . The greatest availability of research on nutritional ergogenic aids was for creatine, caffeine and n-3 fatty acids. Individuals typically use creatine to increase strength and power and may be of particular relevance to older individuals seeking to maintain or build strength, function and potentially cognition. While primary research on creatine as an ergogenic aid has waned in recent years, several SR have been published from 2017 to 2020, including in the ageing population(Reference Beaudart, Rabenda and Simmons17,Reference Chilibeck, Kaviani and Candow20,Reference Forbes, Chilibeck and Candow23,Reference Lanhers, Pereira and Naughton28,Reference Lanhers, Pereira and Naughton29,Reference Stares and Bains39) , and these can be used as resources to guide practitioner advice on creatine supplementation. There is more availability of recent studies examining caffeine(Reference Grgic and Pickering26,Reference Grgic, Grgic and Pickering27,Reference Raya-González, Rendo-Urteaga and Domínguez36,Reference Southward, Rutherfurd-Markwick and Ali38,Reference Grgic, Trexler and Lazinica190) and n-3 fatty acids(Reference Abdelhamid, Hooper and Sivakaran16,Reference Zheng-Tao, Zhang and Zhu31) as ergogenic aids, but these have also been investigated in recent SR as recently as the year this search was conducted. When interpreting this evidence, practitioners should consider if the outcomes of interest align with the performance goals of the client including increased time spent exercising, enhanced endurance, strength or decreased pain. While little of the included research targeted individuals with cardiometabolic risk factors, the use of nutritional ergogenic aids may be common in these individuals to improve exercise endurance and capacity. Thus, when working with individuals with cardiometabolic risk factors, practitioners should consider how to appropriately interpret and modify conclusions and recommendations for clients.
Strengths and limitations
This scoping review had rigorous methods and comprehensively described interventions including both nutrition and physical activity. Another strength of this scoping review was inclusion of populations with a range of cardiometabolic risk that may be representative of the population in economically developed countries, such as the USA. This included individuals who were healthy, overweight or obese, or with cardiometabolic disease. However, the authors did set the parameter that studies would be excluded if they included participants with a BMI of ≥40 kg/m2, with the intention that this relatively arbitrary line may be a proxy for the point at which medical interventions may be necessary beyond ‘standard’ diet and exercise. This is evident in the few studies included that focused on individuals with cardiometabolic disease; most of which included some participants with BMI ≥ 40 kg/m2 and were thus excluded. Future studies may elucidate more relevant measures to stratify individuals who have therapeutic v. ‘general’ needs. Due to the wide breadth of nutrition and physical activity interventions, it was necessary to categorise populations, interventions and outcomes very broadly, thus masking heterogeneity between these studies. Future SR should consider how efficacy of interventions vary according to an individual’s cardiometabolic risk factors, diet and physical activity history and ability, and methods of data collection for dietary intake and physical activity outcomes. Improving understanding of how early interventions may prevent onset or progression of cardiometabolic risk factors prior to disease onset would allow for a development of a framework describing how interventions can be effectively individualised to specific clients but implemented on a broad scale. Increased attention to and rigor of data collection methods, including for dietary and physical activity behaviours, will improve quality of and certainty in evidence to inform practice.
Additional limitations of this scoping review were inclusion of evidence published in the English language only, which may have resulted in missing relevant studies published in other languages, and not all titles/abstracts were screened by two reviewers due to resource constraints and the wide breadth of evidence identified on the topic of interest. These limitations may have resulted in missing relevant articles published on the topics of interest. Also, while this scoping review aimed to identify primary studies published in the 15 years prior to the search and SR published in the 5 years prior to the search, as mentioned, earlier evidence may still be relevant and helpful to practitioners.
Conclusion
Interventions to improve or maintain both nutrition and physical activity can provide clients with the knowledge, skills and tools needed to prevent and treat cardiometabolic risk factors and disease. Several recent SR on the efficacy of nutrition and physical activity mobile apps and nutritional ergogenic aids can serve as evidence-based resources for health practitioners. Though consistent literature has been published examining the effect of providing nutrition and exercise counseling by practitioners in these fields, this evidence has not been synthesised. SR of these targeted interventions may inform scope of practice for dietitians and exercise practitioners working with individuals who are healthy or who have cardiometabolic risk factors. More research is needed examining the long-term effects of nutrition and physical activity interventions on patient-centred health outcomes.
Acknowledgements
Acknowledgements: The authors would like to acknowledge Janet Peterson, Dr PH, RDN, RCEP, WEMT, FACSM for her content expertise and contribution to developing the research questions and eligibility criteria. Financial support: This scoping review was supported by the Academy of Nutrition and Dietetics and the American Council on Exercise (no grant numbers). Conflicts of interest: M.R. is employed by the Academy of Nutrition and Dietetics. J.R. has provided contracting services with the American Council on Exercise. K.J. consults for US Highbush Blueberry Council, The Wonderful Company, Clif Bar & Co, Honey Stinger and NOW Foods. The authors have no other conflicts of interest to disclose. Authorship: All authors contributed to the development of the research question and sub-questions as well as eligibility criteria. M.R. and A.Y. screened article title/abstracts and full texts, extracted data and synthesised evidence. M.R., J.R. and K.J. wrote the first draft of the manuscript and all authors thoroughly reviewed and edited the manuscript and approve of the version submitted. Ethics of human subject participation: not applicable.
Supplementary material
For supplementary material accompanying this paper visit https://doi.org/10.1017/S1368980021002184
