Protein Supplements Are Not for Snacking

People looking to manage their weight with strength-training and protein supplements should consume their supplements during a meal.

The idea that consuming protein before or after a workout helps in strength gains or muscle growth has been subject to some debate. A meta-study of research on protein timing concluded that there wasn’t enough evidence to support the efficacy of timing. That doesn’t stop people from believing that there is a window of opportunity for protein consumption but even if there is one, it appears to be longer than one-hour before and after training. However, a new study on the effects of protein supplementation on weight management says protein supplements should be consumed during a meal if you want to lose weight.

“It may matter when you take your supplements in relation to when you eat meals, so people who consume protein supplements in between meals as snacks may be less likely to be successful in managing their body weight,” said Wayne Campbell, professor of nutrition science from Purdue University and senior author on the study.

Protein supplements are available in ready-to-drink, powdered and solid forms, and often contain whey, casein or soy proteins. They can help with weight gain, weight loss or weight management based on how they are incorporated into an eating plan and taken with meals or as snacks.

“This is really the first time that the issue of timing when supplements are consumed in regard to meals has been looked at,” Hudson said. “This review needs to be followed up by rigorous studies to better evaluate the timing of protein supplements in relationship to meals.”

Their analysis of research studies found that while protein supplementation effectively increased lean mass for all groups, consuming protein supplements with meals helped maintain their body weight while decreasing their fat mass. In contrast, consuming protein supplements between meals promoted weight gain.

The timing likely makes a difference because a person may tend to adjust their calories at a meal time to include the protein supplement.

“Such dietary compensation is likely missing when protein supplements are consumed as snacks. Calories at meal times may not be adjusted to offset the supplement’s calories, thus leading to a higher calorie intake for that day,” said Campbell, whose expertise integrates human nutrition, exercise physiology, and geriatrics. “If the goal is to manage weight, then snacking on protein supplements may be less effective. People who are trying to gain weight may consider consuming protein supplements between meals.”

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Joshua L. Hudson, Robert E. Bergia and Wayne W. Campbell. Effects of protein supplements consumed with meals, versus between meals, on resistance training-induced body composition changes in adults: a systematic review. Nutrition Reviews, 2018.