Whey Protein Before Resistance Exercise Increases Metabolic Rate

Whey Protein Before Resistance Exercise Increases Metabolic Rate

by: Robbie Durand

Most athletes think of supplements like caffeine, green tea, synephrine, etc., as powerful stimulators of metabolism. However, most people don’t realize that consuming whey protein before a resistance exercise bout can be very thermogenic as well.

Acute studies have reported that whey protein isolate (60 grams per day) evaluated over six months resulted in significantly lower hyperinsulinemia (less fat storage potential), lower cortisol levels (lean muscle preservation) and increased ghrelin release (satiety enhancement). A previous study released in Nutrition & Metabolism reported that people on whey protein supplementation lost more weight than a control group receiving maltrodextrins in conjunction with a calorie-restricted diet. Each subject was instructed to consume one supplement 20 minutes before breakfast and one supplement 20 minutes before dinner. The whey protein supplement contained 10 grams of protein per serving as a combination of intact whey protein and peptides. It also contained minerals that were purified from milk. The control group received an isocaloric beverage containing maltodextrin.

After 12 weeks, weight loss was consistently higher in the whey protein subjects, primarily the result of losing body fat (subjects taking whey protein lost 6.1 percent of their body fat mass). The whey protein group subjects also lost significantly less lean muscle mass compared to control subjects. Whey protein may be the perfect fat-loss supplement when dieting for an important event or for targeting fat loss while maintaining lean muscle. Since whey is nutrient dense, but relatively low in energy (~4 kcal/g), supplementation is an efficient method to promote skeletal muscle anabolism while promoting catabolism in fat cells and therefore is hypothesized to improve both muscle growth and fat loss.

More exciting news was recently reported that whey protein taken before exercise can rev up your fat metabolism. To determine whether whey protein supplementation before an acute bout of heavy resistance training would influence post exercise resting energy expenditure (REE) and fat oxidation, eight resistance-trained subjects participated in a double blind two-trial crossover design, where resting energy expenditure and fat oxidation were measured at 7:00 a.m. on four consecutive days. On the second day of trial 1, subjects consumed 376 kJ of either whey protein (18 g of whey protein, 2 g of carbohydrate, 1.5 g of fat) or carbohydrates (1 g of whey protein, 19 g of carbohydrate, 1 g of fat) 20 minutes before a single bout of heavy resistance exercise (nine exercises, 4 sets, 70%-75% 1-repetition maximum). Resting energy expenditure and fat metabolism were measured 24 and 48 h after heavy resistance exercise.

During trial 2, the same protocol was followed except subjects consumed the carbohydrate supplement before heavy resistance exercise. Compared with baseline, REE was elevated significantly in both CHO and PRO at 24 and 48 h after heavy resistance exercise. At 24 h after heavy resistance exercise, resting energy expenditure in response to whey protein was significantly greater compared with carbohydrate.

Fat oxidation increased significantly in both carbohydrate and whey protein group at 24 hours after heavy resistance exercise compared with baseline. No differences were observed in total energy intake, macronutrient intake, or heavy resistance exercise volume.

Timing whey protein before heavy resistance exercise may be a simple and effective strategy to increase energy expenditure by elevating resting energy expenditure the day after heavy resistance exercise. Increasing resting energy expenditure could facilitate reductions in body fat mass and improve body composition if nutritional intake is stable.

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