Related Experiment Video
Updated: Jun 9, 2026

A Chronic High-Intensity Interval Training and Diet-Induced Obesity Model to Maximize Exercise Effort and Induce Physiologic Changes in Rats
Published on: April 28, 2023
Protein intake induced an increase in exercise stimulated fat oxidation during stable body weight
Stijn Soenen1, Guy Plasqui, Astrid J Smeets
1Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Top Institute Food and Nutrition (TIFN), Maastricht University,P.O. Box 616, 6200 MD Maastricht, The Netherlands. S.Soenen@HB.unimaas.nl
Background:
Protein-rich weight-loss diets spare fat-free mass at the cost of fat mass. The objective was to examine if there is a change in stimulated fat oxidation related to protein intake during stable body weight.
Methods:
Subjects' (BMI 22±2kg/m(2), age 25±8 years) maximal fat oxidation (Fat(max)) was assessed during a graded bicycle test, before and after a 3-month dietary-intervention of 2MJ/day supplements exchanged with 2MJ/d of habitual energy intake. The parallel design consisted of protein-rich supplements in the protein group and an isocaloric combination of carbohydrate and fat supplements in the control group. Daily protein intake was determined according to 24-h urine nitrogen. Body composition was measured according to a 4-compartment model by a combination of underwater-weighing technique, deuterium-dilution technique and whole-body dual-energy X-ray absorptiometry (DXA).
Results:
Subjects were weight stable and did not change their physical activity. The protein group (n=12) increased protein intake (11±14g, P<0.05) and had significantly higher daily protein intake vs. control (n=4) (80±21 vs.59±11g, P<0.05). Fat(max) increased significantly in the protein group (0.08±0.08g/min, P<0.01). Fat-free mass increased independent of change in body weight (P<0.01), and fat mass and fat percentage decreased (P<0.05). Change in Fat(max) was a function of change in protein intake (r=0.623, P<0.05), and not of changes in body composition or VO(2)max.
Conclusion:
Increased stimulated fat oxidation was related to increased protein intake.
Related Concept Videos
Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
Exercise and Muscle Performance
Endurance exercises
Endurance exercises involve running, swimming, or cycling, which require repetitive movements with low force output. When a person engages in endurance exercise, a few noticeable changes occur in their skeletal muscles. For instance, the number of capillaries...
Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be met...
Metabolic States of the Body: Fasting and Starvation
Metabolic States of the Body: The Absorptive State
Metabolic States of the Body: The Postabsorptive State
Initially, glycogen stored in the liver is broken down to release glucose into the bloodstream, while glycogen in the muscles is broken down to supply glucose for energy directly within the muscle cells. As glycogen stores diminish,...

