The Lean Living Study

NCT02501889 | Completed

• 1 other identifier: 20154971
• Study Type: interventional
• Target: 100
• Locations: 1 country
• Sites: 1

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.

Conditions

Overweight and Obesity

Keywords

obesity; overweight; weight loss; satiety; walnuts; gastrointestinal peptides

Outcome Measures

Primary Outcomes (2)

• 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.

  2 years

• 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.

  2 years

Secondary Outcomes (1)

• 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.

  2 years

Other Outcomes (2)

• 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.

  2 years

• Satiety- and appetite-related visual analogue scales following meals with or without walnuts in a sample subset, as an exploratory aim.

  2 years

Study Arms (2)

Walnut-rich weight loss diet arm

EXPERIMENTAL

Participants will have an individualized reduced-calorie diet prescription and weight loss counseling session with the project coordinator, who is a registered dietitian. Composition of prescribed diets will be based on individual preferences. During the 6-month intervention, study subjects will participate in individualized counseling and group sessions, with in-person, telephone, email and text message contacts to provide support and behavioral guidance and strategies. All participants will have contact with the project coordinator a minimum of every 1-2 weeks. Walnuts will be provided to participants in the walnut-rich study arm.

Behavioral: Walnut-rich weight loss diet

Standard weight loss diet arm

ACTIVE COMPARATOR

Participants will have an individualized reduced-calorie diet prescription and weight loss counseling session with the project coordinator, who is a registered dietitian. Composition of prescribed diets will be based on individual preferences. During the 6-month intervention, study subjects will participate in individualized counseling and group sessions, with in-person, telephone, email and text message contacts to provide support and behavioral guidance and strategies. Participants assigned to this arm will be instructed to abstain from the consumption of nuts during the study. All participants will have contact with the project coordinator a minimum of every 1-2 weeks.

Behavioral: Standard weight loss diet

Interventions

Walnut-rich weight loss diet BEHAVIORAL

Composition of prescribed diets will be based on individual preferences, with the goal of reduced energy intake and increased energy expenditure. During the 6-month intervention, study subjects will participate in individualized counseling and group sessions, with in-person, telephone, email and text message contacts to provide support and behavioral guidance and strategies. Walnuts will be provided to participants. The overall content of the intervention consists of key elements of cognitive-behavioral therapy for obesity. The physical activity component emphasizes planned aerobic exercise, increased physical activity in the lifestyle, and strength training.

Walnut-rich weight loss diet arm

Standard weight loss diet BEHAVIORAL

Composition of prescribed diets will be based on individual preferences, with the goal of reduced energy intake and increased energy expenditure. During the 6-month intervention, study subjects will participate in individualized counseling and group sessions, with in-person, telephone, email and text message contacts to provide support and behavioral guidance and strategies. The overall content of the intervention consists of key elements of cognitive-behavioral therapy for obesity. The physical activity component emphasizes planned aerobic exercise, increased physical activity in the lifestyle, and strength training.

Standard weight loss diet arm

Eligibility Criteria

• Age: 21 Years - 75 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• University of California, San Diego: lead
• AICR Matching Grant Program (California Walnut Commission and AICR): collaborator

Study Sites (1)

UC San Diego

La Jolla, California, 92093-0901, United States

Location

Related Publications (28)

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• 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.

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• 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.

  PMID: 29202751 DERIVED

MeSH Terms

Conditions

Overweight; Obesity; Weight Loss

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Body Weight Changes

Study Officials

• Cheryl L. Rock, PhD, RD

  University of California, San Diego

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: July 9, 2015
• First Posted: July 17, 2015
• Study Start: August 1, 2015
• Primary Completion: June 1, 2017
• Study Completion: June 1, 2017
• Last Updated: October 26, 2017

Record last verified: 2016-09

Locations

US (1)