Diet Order Effects of Low Fat vs. Low Carb Diets on Body Fat Change

Launched by NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES (NIDDK) · Mar 21, 2024

Keywords

ClinConnect Summary

This clinical trial is studying how the order of different diets—low-fat versus low-carbohydrate—affects weight loss and body fat changes in people who are overweight or obese. In this study, participants will follow one diet for 4 weeks and then switch to the other diet for another 4 weeks. Researchers are particularly interested in whether starting with a low-carbohydrate diet leads to more fat loss compared to starting with a low-fat diet, based on previous shorter studies.

To participate, you should be an adult aged 18 to 50 with a body mass index (BMI) of 25 or higher, meaning you are considered overweight. You'll need to be stable in your weight for the last six months and be willing to follow the study's guidelines. Participants will receive all their meals delivered to their homes and will need to track their weight, physical activity, and some health measurements during the study. There will be a few visits to the NIH for tests and check-ins. If you have certain health conditions or take specific medications, you might not be eligible, so it’s important to discuss with the study team. This trial aims to provide more insights into effective dietary strategies for weight loss.

Gender

ALL

Eligibility criteria

• * INCLUSION CRITERIA:
• In order to be eligible to participate in this study, an individual must meet all of the following criteria:
• • 1. Stated willingness to comply with all study procedures and availability for the duration of the study
• • 2. Adults aged 18-50 years
• • 3. Weight stable (\< +/- 5 percent over past 6 months) as determined by volunteer report
• • 4. Body mass index (BMI) \>= 25 kg/m\^2
• • 5. Agreement to adhere to Lifestyle Considerations throughout the study duration
• EXCLUSION CRITERIA:
• • 1. Subjects with cardiac pacemakers or other implants that may be affected by or affect the DXA measurements
• • 2. Inadequate access to equipment required for the study (e.g., too little refrigerator storage space or a microwave oven that is too small) as determined by discretion of PI and/or study team
• • 3. Evidence of diseases or conditions that may influence appetite (e.g., cancer, diabetes, alterations of smell or taste post COVID-19), diseases or conditions that affect the immune system, or other conditions at the discretion of the PI and/or study team
• • 4. Taking prescription medications or other drugs that may influence metabolism (including but not limited to diet/weight-loss medication, some psychiatric medications, or other medications at the discretion of the PI and/or study team)
• • 5. People unlikely to adhere to a relatively consistent daily and weekly routine and avoid travel during their participation in the study. For example, people with occupations such as pilots, flight attendants, or frequently travel for work or pleasure.
• • 6. Positive pregnancy test or lactating as determined by volunteer report (women only)
• • 7. Inability or unwillingness to use birth control between screening and completion of the study (women only)
• • 8. Symptoms or signs of perimenopause or menopause by volunteer report (women only)
• • 9. Regular vigorous exercise \>150 min per week as determined by volunteer report
• • 10. Alcohol consumption \> 3 drinks per day as determined by volunteer report
• • 11. Regular use of tobacco (smoking, chewing, or vaping), nicotine replacement therapy, or illicit drugs over past 6 months as determined by volunteer report. Subjects may also be excluded based on a urine drug test.
• • 12. Psychological conditions as determined by DSM-5 Self-rated Level 1 Cross-cutting Symptom Measure such as (but not limited to) eating disorders, depression, bipolar disorders, that would be incompatible with safe and successful participation in this study, as determined by investigators
• • 13. Volunteers with strict dietary concerns (e.g. vegetarian or kosher diet, food allergies) or a reported dislike of a significant fraction of the study foods
• • 14. Volunteers unwilling or unable to give informed consent
• • 15. Non-English speakers due to unavailability of required questionnaires in other languages