Whey Protein, but not Carbohydrate, Before Exercise Increases Resting Energy Expenditure

One of the best ways to improve your body composition, by increasing lean muscle mass and decreasing body fat, is to engage in heavy weight lifting.

It’s well-known that people who challenge their bodies with heavy resistance exercises have more muscle than those who only use light weights and easy exercises. And, depending on the diet and other daily activities, these people often have less body fat.

Challenging resistance exercises, like front squats, deadlifts, and Olympic lifts, can improve your body composition by stimulating muscle protein synthesis pathways and enhancing fat oxidation (burning) for several hours after your exercise session has completed.

Scientific studies have shown us that certain foods can enhance the amount of fat burned for energy several hours after the weight lifting session is over, and increase the amount of muscle synthesized.

Specifically, whey protein has been shown in many different scientific studies to increase muscle protein synthesis when take both before and after heavy resistance exercise. The best time to take whey protein for this effect is within 30 minutes before and 30 minutes after.

Recently, researchers from Michigan State University showed that when a whey protein supplement was taken before a heavy weight lifting session, resting energy expenditure (REE) was significantly elevated for 24 hours compared to a carbohydrate-only supplement.

REE is an important measure of the amount of calories you burn in one day and accounts for about 60-75% of your total daily energy expenditure. Thus, if you have a higher REE, you will burn more calories in the day and store less of them as body fat.

In this study, eight experienced weight trainees, (5 men and 3 women), were given either a supplement containing whey protein (18 g protein, 2 g carbs, 1.5 g fat) or Nesquik chocolate (19 g carb, 1 g protein, 1 g fat) randomly on two separate days 20 minutes before a heavy weight training session.   

Although both sessions of resistance exercise (after both the protein and carb drink) increased REE and fat oxidation for 24 and 48 hours after the session was over, the whey protein supplement increased REE significantly more at the 24 hour mark compared to the carb supplement. The differences at 48 hours were insignificant.

The whey protein supplement delivered important amino acids to muscle tissue during the exercise session which were used to enhance muscle protein synthesis for several hours after the exercises were over.  These amino acids help speed muscle recovery and prevent excessive muscle soreness so you can lift heavy and hard again the next day.

Overall, if you’re looking to increase the amount of calories you burn after heavy resistance exercise, which helps you build more muscle and lose more body fat, whey protein AND carbs is the right way to fuel your body post-workout. Take whey protein within 30 minutes before exercise and whey protein plus carbohydrates after exercise for the best effect and watch those fat cells run away in fear. 

Reference:

Timing protein intake increases energy expenditure 24 h after resistance training. Hackney KJ, Bruenger AJ, Lemmer JT. Med Sci Sports Exerc. 2010 May;42(5):998-1003.