Ketogenic Diets for Weight Loss Maintenance: Impact on Energy Expenditure and Appetite in Individuals With Obesity

Purpose

The goal of this clinical trial is to investigate whether a Ketogenic Diet (KD) can increase Total Energy Expenditure (TEE), while benefiting appetite, during weight loss maintenance in reduced-obese individuals.

Condition

  • Obesity

Eligibility

Eligible Ages
Between 18 Years and 65 Years
Eligible Sex
All
Accepts Healthy Volunteers
No

Inclusion Criteria

  • BMI 30-45 kg/m2 - Both men and women - Age between 18-65 years - Sedentary to moderately active (<2 h/wk of moderate, structured, intentional, exercise)

Exclusion Criteria

  • Pregnancy or lactation - Daily use of tobacco (>1 pk/wk) - Change in weight greater than 5 lb in the previous 3 months - Cognitive impairment - Previous bariatric surgery - History of eating disorder - Presence of any condition (e.g. DM2, PCOS, inflammatory disease, untreated thyroid disease, fluid overload states such as chronic kidney disease, congestive heart failure, or cirrhosis) - Use of any medication (e.g., glucocorticoid, GLP-1 analogues, hormone replacement therapy) deemed to interfere with study outcomes. - Pre-menopausal women will need to have a regular menstrual cycle (28+/-2 days) or be on hormonal contraceptives - Fasting glucose plasma concentration >125 mg/dl and/or HbA1c > 6.4%

Study Design

Phase
N/A
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Treatment
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Ketogenic Diet 		Participants randomized to the ketogenic diet will follow a diet with 5% energy from carbohydrates, 70% from fat, and 25% from protein for 6 weeks. The first 2 of the 6 weeks weeks will be a gradual refeeding, with participants slowly withdrawing from the meal replacements used during the 4-week weight loss phase, while introducing more food.
  • Behavioral: Diet Therapy
    Participants will be provided food to meet the ketogenic diet prescription for the 6-week weight maintenance phase.
  • Behavioral: Calorie Restriction
    Participants will follow a commercial low-energy diet and be provided with meal replacements for 4 weeks aiming to achieve a minimum of 5% weight loss.
  • Behavioral: Behavioral Support
    Participants will meet weekly with a registered dietitian, for a 20-minute consultation throughout the entire study period (10 weeks) to increase engagement and improve adherence and retention.
Active Comparator
Low-Fat Diet 		Participants randomized to the low-fat diet will follow a diet with 50% energy from carbohydrates, 25% energy from fat, and 25% energy from protein for 6 weeks. The first 2 of the 6 weeks weeks will be a gradual refeeding, with participants slowly withdrawing from the meal replacements used during the 4-week weight loss phase, while introducing more food.
  • Behavioral: Calorie Restriction
    Participants will follow a commercial low-energy diet and be provided with meal replacements for 4 weeks aiming to achieve a minimum of 5% weight loss.
  • Behavioral: Behavioral Support
    Participants will meet weekly with a registered dietitian, for a 20-minute consultation throughout the entire study period (10 weeks) to increase engagement and improve adherence and retention.
  • Behavioral: Diet Therapy
    Participants will have food provided to meet the standard low-fat diet prescription for the 6-week weight maintenance phase.

Recruiting Locations

University of Alabama at Birmingham
Birmingham, Alabama 35294
Contact:
Catia Martins, PhD
2059347922
catia197@uab.edu

More Details

Status
Recruiting
Sponsor
University of Alabama at Birmingham

Study Contact

Catia Martins, PhD
205-934-7922
catia197@uab.edu

Detailed Description

The total duration of the intervention will be 10 weeks. Participants will first undergo 4 weeks of a low-energy diet (LED), aiming to induce a minimum of 5% weight loss (weight loss phase). Those who achieve at least a 5% weight loss will then be randomized (1:1) to a 6-week weight loss maintenance (WLM) diet, either a KD or an isocaloric low-fat diet, with the first 2 weeks being a gradual refeeding.