Dietary protein to maximize resistance training: a review and examination of protein spread and change theories

Abstract

An appreciable volume of human clinical data supports increased dietary protein for greater gains from resistance training, but not all findings are in agreement. We recently proposed "protein spread theory" and "protein change theory" in an effort to explain discrepancies in the response to increased dietary protein in weight management interventions. The present review aimed to extend "protein spread theory" and "protein change theory" to studies examining the effects of protein on resistance training induced muscle and strength gains. Protein spread theory proposed that there must have been a sufficient spread or % difference in g/kg/day protein intake between groups during a protein intervention to see muscle and strength differences. Protein change theory postulated that for the higher protein group, there must be a sufficient change from baseline g/kg/day protein intake to during study g/kg/day protein intake to see muscle and strength benefits. Seventeen studies met inclusion criteria. In studies where a higher protein intervention was deemed successful there was, on average, a 66.1% g/kg/day between group intake spread versus a 10.2% g/kg/day spread in studies where a higher protein diet was no more effective than control. The average change in habitual protein intake in studies showing higher protein to be more effective than control was +59.5% compared to +6.5% when additional protein was no more effective than control. The magnitudes of difference between the mean spreads and changes of the present review are similar to our previous review on these theories in a weight management context. Providing sufficient deviation from habitual intake appears to be an important factor in determining the success of additional protein in enhancing muscle and strength gains from resistance training. An increase in dietary protein favorably effects muscle and strength during resistance training.

Higher Total Protein Intake and Change in Total Protein Intake Affect Body Composition but Not Metabolic Syndrome Indexes in Middle-Aged Overweight and Obese Adults Who Perform Resistance and Aerobic Exercise for 36 Weeks

“…These observations complement our previous research showing that changes in protein intake predict changes in bone mineral density (inverse association) in older women (59) and support that muscle and strength gains from resistance training are augmented by greater increases in habitual TPro from before to during the intervention (60). Collectively, these findings indicate that CTPro should be carefully documented and assessed as a potential BC modifier.…”

The acute effects of caffeine intake on time under tension and power generated during the bench press movement

“…Optimization of resistance training and the pattern of adaptive changes related to the development of muscular strength and power have been the focus of interest of scientists from different fields of studies [3][4][5][6]. In addition to training, diet and supplementation also have a significant effect on adaptation and post-exercise responses [7][8][9][10][11][12]. To date, few supplements have been shown to have a direct ergogenic effect on physical capacity.…”

A Pilot Study Examining the Effects of 8-Week Whey Protein versus Whey Protein Plus Creatine Supplementation on Body Composition and Performance Variables in Resistance-Trained Women

“…This hypothesis is not unfounded given that a 14 g bolus of supplemental protein has been shown to reduce food intake during a subsequent meal [27] . Notwithstanding, our finding that total protein intake did not increase in both groups is problematic given that others have suggested that protein supplementation has to be 'deliberate' in order to realize optimal training adaptations; specifically intakes should exceed 66% of pre-supplementation values [28] or be greater than 2.0 g/kg/day in men [29] and subjects in both groups consumed ∼ 1.1-1.3 g/kg during T2 and T3. Given that protein metabolism has been reported to be minimally affected by gender [30] , we surmise that women in the current study may have experienced greater increases in muscle mass if daily protein intakes were ∼ 2.0 g/kg/day during the study.…”