Protein Restriction (PR) for Weight Loss (PR)

Prolonged dietary protein restriction has been shown to increase energy expenditure in mice simultaneously with an increase in plasma FGF21 levels. In overfeeding studies, a protein-restricted diet reduces weight gain in both mice and humans compared with normal and high-protein diets. Further, in energy balance studies, when lean men are provided with a protein-restricted diet for five weeks, an increase in energy intake was necessary to obtain their body weight. However, whether the effect of a protein-restricted diet is the same when consumed by overweight to obese men has divergent results in both mice and humans.

Study Overview

• Status: Completed
• Conditions: Diet, Healthy, Body Weight
• Intervention / Treatment: Other: Restricted dietary protein; Other: Habitual diet

Detailed Description

The present study is a randomised intervention study. Inclusion criteria for the study are healthy males age between 25 and 45 years, BMI between 26 and 32, low physical activity level (low aerobic capacity with a VO2 - peak of 30 ± 10 mL/min/kg), non-smoker, not using snuff, not suffering from diabetes, hypertension, or any daily medication use and a high dietary protein intake (≥1,5 g/kg body weight/day). Before the intervention period, the participants complete a two-week run-in period. The run-in period is designed to collect more detailed information about the participant's habitual diet, body weight, and physical activity pattern, as well as habituate the participants in the various tasks they have to complete during the intervention. Then a five-week intervention period is initiated where the participants are randomized to follow one of the following diets for 5 weeks: 1) a diet reduced in protein, replaced by primary carbohydrates (11 E% Protein, 50 E% carbohydrates, 37 E% fat), and 2) a control diet comprising habitual protein content (21E% Protein, 40 E% carbohydrates, 37 E% fat).

In the five-week intervention period, all food and drinks (besides water and coffee) are provided for the participant. All food is weighed to 1 gram of accuracy in meal portions for a seven-day cycle and is delivered to the participant.

During the intervention the volunteers participate in six test days, one every week during the intervention. 48 hours prior to the weekly test, the participants are asked to abstaine from vigorous physical activity. On all the test days, the participants arrive in the morning in a fasted state (no food or drink after 10 pm the night before) by passive transportation.

On the first test day (WT0), body composition is determined by DXA scan, and the total body water content is measured using bioimpedance analysis. Then resting metabolic rate is measured. Still, in the supine position, a blood sample is obtained from an antecubital vein. Biopsies are taken at baseline and at the end of the intervention (WT5). A fat biopsy is obtained from periumbilical subcutaneous adipose tissue and a muscle biopsy from the vastus lateralis muscle. On test day 3, halfway through the intervention, body composition, body water, and resting metabolic rate are measured, and blood is sampled from an antecubital vein. On week tests 1, 2, and 4, resting metabolic rate is measured, and blood sampled. At all visits to the institute, body weight is also measured.

During the intervention the participants wear a Sens motion sensor to monitor daily activity level.

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Copenhagen, Denmark, 2100
    • University of Copenhagen

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• BMI between 26 and 32 Low physical activity level Non-smoker Not using snuff Not suffering from diabetes, hypertension, or any daily medication use High protein intake (≥1,5 g/kg body weight/day)

Exclusion Criteria:

-

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Restricted dietary protein; 5 week intake of a isocaloric diet restricted in protein	Other: Restricted dietary protein; Participants will be allocated to 5 week isocaloric restricted protein intake; Other: Habitual diet; Participants will be follow their habitual, high protein intake
Experimental: Habitul diet; 5 week intake of habitual, high protein diet	Other: Restricted dietary protein; Participants will be allocated to 5 week isocaloric restricted protein intake; Other: Habitual diet; Participants will be follow their habitual, high protein intake

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body weight	The effect of a prolonged moderate protein-restricted diet on body weight in obese participants.	5 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
FGF21	study plasma FGF21 concentrations in relation to energy turnover	5 weeks

Collaborators and Investigators

• Sponsor: University of Copenhagen
• Investigators: Principal Investigator: Bente Kiens, D.Sci, University of Copenhagen

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2021
• Primary Completion (Actual): December 31, 2023
• Study Completion (Actual): December 31, 2023

Study Registration Dates

• First Submitted: February 8, 2024
• First Submitted That Met QC Criteria: February 8, 2024
• First Posted (Actual): February 16, 2024

Study Record Updates

• Last Update Posted (Actual): February 16, 2024
• Last Update Submitted That Met QC Criteria: February 8, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Body Weight Changes; Weight Loss; Body Weight
• Other Study ID Numbers: ALyster

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No