High Protein Diet, Resistance & Anaerobic Exercise and Energy Deficits
Title: Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial
Author: Longland et al
Journal: American Journal of Clinical Nutrition (March 2016, 103)
Objective: The purpose of this study was to conduct a proof-of principle trial to test whether manipulation of dietary protein intake during a marked energy deficit in addition to intense exercise training would affect changes in body composition.
Fat burning and weight loss while maintaining lean skeletal muscle is the holy grail of diet and exercise.
There is a fundamental principle of weight loss which states calories burned must exceed calories consumed in order for there to be net negative calories and thus loss of weight. When discussing the biochemistry of this activity, you are either placing your body in a fasting mode, or during prolonged periods of time, potentially in starvation mode.
In either context, your body turns to energy reserves, including both muscle and fat, to make up for the lack of dietary intake. Inevitably, this activity leads to breakdown of that hard earned skeletal muscle and most people would like to avoid this. The question is: is it possible and how?
In a typical negative energy state, about 20-30% of weight loss is skeletal muscle while the rest is adipose tissue. Research has already shown us that increasing your dietary protein intake during periods of energy deficit can help attenuate the lossof lean muscle mass. Resistance training has also been shown to attenuate loss. It appears to stimulate more myofibrillar protein synthesis resulting in a greater shift of catabolic activity to fat cells. High intensity interval training may accomplish the same goal.
The authors of this study wanted to know if individuals with an energy deficit and a high- or low-protein diet would attenuate the loss or promote the gain of lean body muscle while resistance training and interval training were performed.
They used a single-blind, randomized, parallel-group prospective trial.
During a 4-wk period, they provided low energy ( meaning a 40% reduction compared with requirements) diets, providing 33 kcal/ kg lean body muscle, to young men who were randomly assigned (n = 20/group) to consume either a lower-protein (1.2 g /kg /day) control diet (CON) or a higher-protein (2.4 g /kg /day) diet (PRO).
All subjects performed resistance exercise training combined with high intensity interval training for 6 days /wk.
A 4-compartment model assessment of body composition was made pre- and post intervention.
As a result of the intervention, lean body mass increased (P , 0.05) in the high protein group (1.2 ± 1.0 kg) and to a greater extent (P , 0.05) compared with the control group (0.1 ± 1.0 kg).
The high protein group had a greater loss of fat mass than did the control group (PRO: 24.8 ± 1.6 kg; CON: 23.5 ± 1.4kg; P , 0.05).
All measures of exercise performance improved similarly in the PRO and CON groups as a result of the intervention with no effect of protein supplementation (meaning they adjusted their model for protein consumption).
Changes in serum cortisol during the intervention were associated with changes in body fat (r = 0.39, P = 0.01) and lean body mass (r = -0.34, P = 0.03).
During an energy deficit, 2.4 g/kg protein was superior to 1.2 g/kg protein for promoting production of lean body muscle and fat loss in individuals completing both resistance training and high energy interval training.
In different words, increasing your protein intake during dieting, when combined with exercise, helps you gain more muscle and lose more fat.
Longland, T. M., Oikawa, S. Y., & Mitchell, C. J. (2016). Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. American Journal of Clinical Nutrition, 103(3), 738-746. doi:10.3945/ajcn.115.119339