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

Summary

Background:

In a previous study, participants were lived at the NIH and randomly received either a low-fat or a low-carbohydrate diet for 2 weeks and then switched to the other diet for 2 more weeks. Participants who received the low-carbohydrate diet first lost more body fat at the end of the study than those who received the low-fat diet first. Researchers want to see if they can repeat that result in a longer weight loss study when participants live at home.

Objective:

To test the effects of diet order in people receiving either a low-fat or low-carbohydrate diet first for 4 weeks and then immediately switched to the other diet for another 4 weeks.

Eligibility:

Adults aged 19 to 50 years with a body mass index of 25 or more.

Design:

Participants will complete the study at their homes, but there will be 3 required visits to the NIH. Participants will drink a special type of water 2 weeks before the baseline NIH visit and collect urine samples at home to measure how many calories they burn. Before the diets begin, participants will visit the NIH for baseline testing when they will have a metabolism test while relaxing in a bed with a plastic hood over their head to collect the air they breathe out. They will have scans to measure their bone density and how much muscle and body fat they have. They will give stool, blood, and urine samples.

Participants will be asked to eat a specific diet for 4 weeks followed by a different diet for 4 weeks. All meals will be delivered to the participants' homes. They will eat only the foods delivered.

Participants will weigh themselves daily. They will wear a monitor to track their physical activity and a sensor to measure their glucose levels. They will prick their finger each morning to test a drop of blood for ketones. Participants will meet virtually as a group with the study team weekly. Participants will have two more NIH visits towards the end of each diet period....

Conditions

• Overweight
• Obesity

Interventions

OTHER

Low-carbohydrate Diet

Consisting of 15 percent protein, 75 percent fat, and 10 percent carbohydrate

OTHER

Low-fat Diet

Consisting of 15 percent protein, 10 percent fat, and 75 percent carbohydrate

Sponsors & Collaborators

• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

  lead NIH

Principal Investigators

• Valerie L Darcey · National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

50 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2024-08-28

Primary Completion

2026-07-31

Completion

2026-07-31

Countries

• United States

Study Locations