Thermogenenic Responses to Fasting and Overfeeding in Women

Summary

This study plans to learn more about why menopause increases the risk of weight gain. During and after menopause, women are prone to increased weight gain. The weight gained is primarily body fat, particularly visceral or abdominal body fat. The excess gain in abdominal fat during menopause increases the risk of chronic metabolic diseases such as heart disease and diabetes. The increase in weight and body fat with menopause may be due to changes in metabolism related to the loss of estrogen. This study plans to compare how the metabolism of premenopausal and postmenopausal women responds to changes in energy intake. The investigators will compare the changes in energy expenditure that occur during a period of acute fasting (24 hours) and a period of consuming excess calories (overfeeding).

Conditions

• Obesity

Interventions

OTHER

Eucalaloric feeding

Participants will complete a 3-day diet run-in followed by an 24-hr in-patient visit in the room calorimeter. The energy content of the diet will be REE x 1.5 (30% fat, 55% carbohydrate, 15% protein). On the study day, will arrive at 7 AM and an IV catheter will be placed for blood draws, as described in the research plan. Participants will then enter the calorimeter at 0800, exit at 0700 the following day. Participants will be instructed to engage in primary sedentary behaviors. The energy content of the diet will be 1.3 x REE (\~30% fat, 55% carbohydrate, and 15% protein at each meal). Breakfast will account for \~25% and lunch and dinner \~30-35% of total energy needs. Meals will be provided at 0900, 1300, and 1800, and a light snack will be provided at 2000.

OTHER

Acute Fasting

Participants will complete a 3d diet run-in followed by an 24h in-patient visit in the room calorimeter. The energy content of the diet will be REE x 1.5 (30% fat, 55% carbohydrate, 15% protein). On the study day, will arrive at 7 AM and an IV catheter will be placed for blood draws, as described in the research plan. Participants will then enter the calorimeter at 0800, exit at 0700 the following day. Participants will be instructed to engage in primary sedentary behaviors. Participants will complete a 24 hour fast while in the calorimeter. They will be permitted to consume non-caloric beverages (i.e., water, non-caloric and non-caffeinated soft drinks, caffeine-free tea, or decaffeinated coffee) but refrain from consuming any caloric food or beverages. Upon exiting the calorimeter, participants will be provided a meal from the University of Colorado Hospital Patient Kitchen.

OTHER

Acute Overfeeding

Participants will complete a 3d diet run-in followed by an 24h in-patient visit in the room calorimeter. The energy content of the diet will be REE x 1.5 (30% fat, 55% carbohydrate, 15% protein). On the study day, will arrive at 7 AM and an IV catheter will be placed for blood draws, as described in the research plan. Participants will then enter the calorimeter at 0800, exit at 0700 the following day. Participants will be instructed to engage in primary sedentary behaviors. The energy content of the diet will be 200% of energy requirements, based on EE measured during the eucaloric condition. Macronutrient intake will be 3% protein, 51% carbohydrate, and 46% fat. Breakfast will account for \~25% and lunch and dinner \~30-35% of total energy needs. Meals will be provided at 0900, 1300, and 1800, and a light snack will be provided at 2000.

Sponsors & Collaborators

• University of Colorado, Denver

  lead OTHER

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2025-01-01

Primary Completion

2029-12-31

Completion

2030-12-31

Countries

• United States

Study Locations