Clinical trial NCT02501889: The Lean Living Study
Official title: Walnut Consumption in a Weight Loss Intervention: Effects on Weight Change, Satiety and Potential Mediating Factors
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Overweight and Obesity
Keywords: obesity
overweight
weight loss
satiety
walnuts
gastrointestinal peptides
Lead sponsor: University of California, San Diego
Sponsor class: OTHER
Collaborators: name: AICR Matching Grant Program (California Walnut Commission and AICR)
First posted: 2015-07-17
Enrollment: 100
Sex: ALL
Minimum age (years): 21
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: This study investigates whether walnuts help to promote weight loss, associated with increased meal satiety and satisfaction, in 100 overweight and obese men and women who are participating in a 6-month behavioral weight loss intervention. Participants will be randomly assigned to a walnut-enriched reduced-calorie diet or a standard reduced-calorie diet. Body weight, risk factors for cardiovascular disease, and self-reported feelings relevant to satiety and appetite will be measured at baseline and 3- and 6-month follow-up. Also, the response of gastrointestinal tract hormones following meals with or without walnuts will be measured in a subset of study participants (n=20). Results from this study will contribute to understanding the role of nuts in weight control, including further knowledge of the mechanisms, and will expand knowledge of how nuts in the diet may contribute to the prevention and management of obesity.

Detailed description: Epidemiological studies have linked regular consumption of nuts with lower body mass index and reduced likelihood of weight gain in adulthood. Several mechanisms have been proposed to explain why nuts may facilitate weight management, including their high satiety property which may promote dietary compensation with reduced subsequent energy intake. Although proposed as a possible mediating factor, satiety and satiation in relation to nuts or nut-containing meals have been examined in only a few previous studies. The effects of nut consumption in the context of a weight loss intervention have been examined in only five previously-published randomized studies, which have tested the effects of almonds, pistachios or peanuts (but not walnuts) and have had mixed results.

This project is a study to investigate the effects of a walnut-enriched vs. standard reduced-energy diet on body weight and satiety via pre- and post-meal ratings scales, as well as exploring the response of satiety- and appetite-related gastrointestinal peptides to meals with or without walnuts in a sample subset.

The specific aims of this study are:

1. To compare the effects of a walnut-enriched reduced-energy diet to a standard reduced-energy diet on body weight and cardiovascular disease risk factors in a sample of overweight and obese adults in an intensive 6-month weight loss intervention.
2. To examine whether there is a differential response in satiety- and appetite-related ratings scales in association with a walnut-enriched reduced-energy diet and a standard reduced-energy diet among the participants in this weight-loss study.
3. To examine the response of satiety- and appetite-related gastrointestinal peptides (ghrelin, cholecystokinin, glucagon-like peptide, and peptide YY), to meals with or without walnuts in a sample subset, as an exploratory aim.

The first two aims will be addressed in a randomized controlled study involving 100 overweight or obese men and women assigned to a walnut-enriched reduced-energy diet or a standard reduced-energy diet in the context of a 6-month intensive weight loss intervention. Subjective satiety- and appetite-related ratings will be collected at specific intervals before lunch and dinner using visual analogue scales. Postprandial gastrointestinal peptide response to a meal with or without walnuts, the third and exploratory aim, will be measured in a subset of study participants (n=20) using a within-subject crossover study design.

The investigators hypothesize that participants assigned to the walnut-enriched diet study arm will have greater weight loss and overall better improvements in cardiovascular disease risk factors, and that ratings of hunger, fullness, and anticipated prospective consumption will differ from those of participants assigned to the standard reduced-energy diet. The investigators hypothesize that postprandial satiety- and appetite-related gastrointestinal peptides, which play a role in short-term control of appetite and may be biomarkers of satiety, may differ in response to different isocaloric meal composition. Results from this study will contribute to understanding the role of nuts in weight control, including further knowledge of the explanatory mechanisms, and will expand knowledge of how nuts in the diet may contribute to the prevention and management of obesity.

Eligibility criteria: Inclusion Criteria:

* aged 21 years and older
* BMI \>27.0 kg/m2 and \<40 kg/m2
* non-smoker
* willing and able to participate in clinic visits, group sessions, telephone, and internet communications at specified intervals
* able to provide data through questionnaires and by telephone
* willing to maintain contact with the investigators for 6 months
* willing to allow blood collections
* no known allergy to tree nuts
* capable of performing a simple test for assessing cardiopulmonary fitness

Exclusion Criteria:

* inability to participate in physical activity because of severe disability
* a history or presence of a comorbid diseases for which diet modification and increased physical activity may be contraindicated
* smoker
* self-reported pregnancy or breastfeeding or planning a pregnancy within the next year
* currently actively involved in another diet intervention study or organized weight loss program
* a history or presence of a significant psychiatric disorder or any other condition that, in the investigator's judgement, would interfere with participation in the trial

Primary outcomes:
measure: Change in body weight in response to being assigned a walnut-enriched reduced-energy diet or a standard reduced-energy diet in an intensive 6-month weight loss intervention.
timeFrame: 2 years
measure: Change in cardiovascular disease risk factors in response to being assigned a walnut-enriched reduced-energy diet or a standard reduced-energy diet in an intensive 6-month weight loss intervention.
timeFrame: 2 years
Secondary outcomes:
measure: Satiety- and appetite-related visual analogue scales in response to being prescribed a walnut- enriched reduced-energy diet or a standard reduced-energy diet among the participants in the weight-loss intervention.
timeFrame: 2 years
Other outcomes:
measure: Postprandial blood levels of satiety- and appetite-related gastrointestinal peptides (ghrelin, cholecystokinin, glucagon-like peptide, and peptide YY) following meals with or without walnuts in a sample subset, as an exploratory aim.
timeFrame: 2 years
measure: Satiety- and appetite-related visual analogue scales following meals with or without walnuts in a sample subset, as an exploratory aim.
timeFrame: 2 years
Locations:
city: La Jolla
country: United States
facility: UC San Diego
state: California
Study officials:
affiliation: University of California, San Diego
name: Cheryl L. Rock, PhD, RD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Abazarfard Z, Salehi M, Keshavarzi S. The effect of almonds on anthropometric measurements and lipid profile in overweight and obese females in a weight reduction program: A randomized controlled clinical trial. J Res Med Sci. 2014 May;19(5):457-64.
citation: Alper CM, Mattes RD. Effects of chronic peanut consumption on energy balance and hedonics. Int J Obes Relat Metab Disord. 2002 Aug;26(8):1129-37. doi: 10.1038/sj.ijo.0802050.
citation: Babio N, Toledo E, Estruch R, Ros E, Martinez-Gonzalez MA, Castaner O, Bullo M, Corella D, Aros F, Gomez-Gracia E, Ruiz-Gutierrez V, Fiol M, Lapetra J, Lamuela-Raventos RM, Serra-Majem L, Pinto X, Basora J, Sorli JV, Salas-Salvado J; PREDIMED Study Investigators. Mediterranean diets and metabolic syndrome status in the PREDIMED randomized trial. CMAJ. 2014 Nov 18;186(17):E649-57. doi: 10.1503/cmaj.140764. Epub 2014 Oct 14.
citation: Bes-Rastrollo M, Wedick NM, Martinez-Gonzalez MA, Li TY, Sampson L, Hu FB. Prospective study of nut consumption, long-term weight change, and obesity risk in women. Am J Clin Nutr. 2009 Jun;89(6):1913-9. doi: 10.3945/ajcn.2008.27276. Epub 2009 Apr 29.
citation: Blom WA, Lluch A, Stafleu A, Vinoy S, Holst JJ, Schaafsma G, Hendriks HF. Effect of a high-protein breakfast on the postprandial ghrelin response. Am J Clin Nutr. 2006 Feb;83(2):211-20. doi: 10.1093/ajcn/83.2.211.
citation: Brennan AM, Sweeney LL, Liu X, Mantzoros CS. Walnut consumption increases satiation but has no effect on insulin resistance or the metabolic profile over a 4-day period. Obesity (Silver Spring). 2010 Jun;18(6):1176-82. doi: 10.1038/oby.2009.409. Epub 2009 Nov 12.
citation: Brennan IM, Luscombe-Marsh ND, Seimon RV, Otto B, Horowitz M, Wishart JM, Feinle-Bisset C. Effects of fat, protein, and carbohydrate and protein load on appetite, plasma cholecystokinin, peptide YY, and ghrelin, and energy intake in lean and obese men. Am J Physiol Gastrointest Liver Physiol. 2012 Jul;303(1):G129-40. doi: 10.1152/ajpgi.00478.2011. Epub 2012 May 3.
citation: Casas-Agustench P, Lopez-Uriarte P, Bullo M, Ros E, Gomez-Flores A, Salas-Salvado J. Acute effects of three high-fat meals with different fat saturations on energy expenditure, substrate oxidation and satiety. Clin Nutr. 2009 Feb;28(1):39-45. doi: 10.1016/j.clnu.2008.10.008. Epub 2008 Nov 17.
citation: Delzenne N, Blundell J, Brouns F, Cunningham K, De Graaf K, Erkner A, Lluch A, Mars M, Peters HP, Westerterp-Plantenga M. Gastrointestinal targets of appetite regulation in humans. Obes Rev. 2010 Mar;11(3):234-50. doi: 10.1111/j.1467-789X.2009.00707.x.
citation: Diepvens K, Haberer D, Westerterp-Plantenga M. Different proteins and biopeptides differently affect satiety and anorexigenic/orexigenic hormones in healthy humans. Int J Obes (Lond). 2008 Mar;32(3):510-8. doi: 10.1038/sj.ijo.0803758. Epub 2007 Nov 27.
citation: Foster GD, Shantz KL, Vander Veur SS, Oliver TL, Lent MR, Virus A, Szapary PO, Rader DJ, Zemel BS, Gilden-Tsai A. A randomized trial of the effects of an almond-enriched, hypocaloric diet in the treatment of obesity. Am J Clin Nutr. 2012 Aug;96(2):249-54. doi: 10.3945/ajcn.112.037895. Epub 2012 Jun 27.
citation: Gibbons C, Caudwell P, Finlayson G, Webb DL, Hellstrom PM, Naslund E, Blundell JE. Comparison of postprandial profiles of ghrelin, active GLP-1, and total PYY to meals varying in fat and carbohydrate and their association with hunger and the phases of satiety. J Clin Endocrinol Metab. 2013 May;98(5):E847-55. doi: 10.1210/jc.2012-3835. Epub 2013 Mar 18.
citation: Gibbons C, Finlayson G, Dalton M, Caudwell P, Blundell JE. Metabolic Phenotyping Guidelines: studying eating behaviour in humans. J Endocrinol. 2014 Aug;222(2):G1-12. doi: 10.1530/JOE-14-0020.
citation: Karhunen LJ, Juvonen KR, Flander SM, Liukkonen KH, Lahteenmaki L, Siloaho M, Laaksonen DE, Herzig KH, Uusitupa MI, Poutanen KS. A psyllium fiber-enriched meal strongly attenuates postprandial gastrointestinal peptide release in healthy young adults. J Nutr. 2010 Apr;140(4):737-44. doi: 10.3945/jn.109.115436. Epub 2010 Feb 10.
citation: Kirkmeyer SV, Mattes RD. Effects of food attributes on hunger and food intake. Int J Obes Relat Metab Disord. 2000 Sep;24(9):1167-75. doi: 10.1038/sj.ijo.0801360.
citation: Leidy HJ, Apolzan JW, Mattes RD, Campbell WW. Food form and portion size affect postprandial appetite sensations and hormonal responses in healthy, nonobese, older adults. Obesity (Silver Spring). 2010 Feb;18(2):293-9. doi: 10.1038/oby.2009.217. Epub 2009 Jul 23.
citation: Lejeune MP, Westerterp KR, Adam TC, Luscombe-Marsh ND, Westerterp-Plantenga MS. Ghrelin and glucagon-like peptide 1 concentrations, 24-h satiety, and energy and substrate metabolism during a high-protein diet and measured in a respiration chamber. Am J Clin Nutr. 2006 Jan;83(1):89-94. doi: 10.1093/ajcn/83.1.89.
citation: Li Z, Song R, Nguyen C, Zerlin A, Karp H, Naowamondhol K, Thames G, Gao K, Li L, Tseng CH, Henning SM, Heber D. Pistachio nuts reduce triglycerides and body weight by comparison to refined carbohydrate snack in obese subjects on a 12-week weight loss program. J Am Coll Nutr. 2010 Jun;29(3):198-203. doi: 10.1080/07315724.2010.10719834.
citation: Martinez-Gonzalez MA, Corella D, Salas-Salvado J, Ros E, Covas MI, Fiol M, Warnberg J, Aros F, Ruiz-Gutierrez V, Lamuela-Raventos RM, Lapetra J, Munoz MA, Martinez JA, Saez G, Serra-Majem L, Pinto X, Mitjavila MT, Tur JA, Portillo MP, Estruch R; PREDIMED Study Investigators. Cohort profile: design and methods of the PREDIMED study. Int J Epidemiol. 2012 Apr;41(2):377-85. doi: 10.1093/ije/dyq250. Epub 2010 Dec 20. No abstract available.
citation: Mattes RD, Kris-Etherton PM, Foster GD. Impact of peanuts and tree nuts on body weight and healthy weight loss in adults. J Nutr. 2008 Sep;138(9):1741S-1745S. doi: 10.1093/jn/138.9.1741S.
citation: Mattes RD, Dreher ML. Nuts and healthy body weight maintenance mechanisms. Asia Pac J Clin Nutr. 2010;19(1):137-41.
citation: Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB. Changes in diet and lifestyle and long-term weight gain in women and men. N Engl J Med. 2011 Jun 23;364(25):2392-404. doi: 10.1056/NEJMoa1014296.
citation: Natoli S, McCoy P. A review of the evidence: nuts and body weight. Asia Pac J Clin Nutr. 2007;16(4):588-97.
citation: Pelkman CL, Fishell VK, Maddox DH, Pearson TA, Mauger DT, Kris-Etherton PM. Effects of moderate-fat (from monounsaturated fat) and low-fat weight-loss diets on the serum lipid profile in overweight and obese men and women. Am J Clin Nutr. 2004 Feb;79(2):204-12. doi: 10.1093/ajcn/79.2.204.
citation: Rajaram S, Sabate J. Nuts, body weight and insulin resistance. Br J Nutr. 2006 Nov;96 Suppl 2:S79-86. doi: 10.1017/bjn20061867.
citation: Sabate J, Cordero-Macintyre Z, Siapco G, Torabian S, Haddad E. Does regular walnut consumption lead to weight gain? Br J Nutr. 2005 Nov;94(5):859-64. doi: 10.1079/bjn20051567.
citation: Wien MA, Sabate JM, Ikle DN, Cole SE, Kandeel FR. Almonds vs complex carbohydrates in a weight reduction program. Int J Obes Relat Metab Disord. 2003 Nov;27(11):1365-72. doi: 10.1038/sj.ijo.0802411.
citation: Rock CL, Flatt SW, Barkai HS, Pakiz B, Heath DD. Walnut consumption in a weight reduction intervention: effects on body weight, biological measures, blood pressure and satiety. Nutr J. 2017 Dec 4;16(1):76. doi: 10.1186/s12937-017-0304-z.