If you do this before or after a workout, you could be taking years off your life

Photo: Edgar Chaparro

If you have ever completed an intense workout and reached for a protein shake or bar afterward, you know it’s a great feeling to eat something that is solidifying the extreme work that you just put in. Unfortunately, researchers from the University of Sydney have some bad news for protein shake lovers. While these types of amino acids are affective at building muscle in the short term, they might have some uglier long term effects.

The recent study found that an overload on this type of protein can decrease your lifespan, have negative effects on your mood, and lead to weight gain, but the researchers also have advice on what you should do instead.

The negative longterm health effects of protein shakes and bars

While high consumption of amino acids is beneficial for building muscle mass in the short term, it could lead to health issues later in life.

The study, published in Nature Metabolism, found that branch-chain amino acids (BCAAs), which are known to deliver muscle-building benefits, may also reduce your lifespan, harm your mood, and lead to weight gain if consumed excessively.

To study this topic, the team used instruments at the university’s core research facility, Sydney Imaging, to examine the impacts that dietary BCAAs, and other essential amino acids like tryptophan, had on the health and body composition of mice.

The research found that supplementation of BCAAs resulted in high levels of BCAAs in the blood, which then competed with tryptophan for transport into the brain.

“Tryptophan is the sole precursor for the hormone serotonin, which is often called the ‘happiness chemical’ for its mood-enhancing effects and its role in promoting sleep…but serotonin does more than this, and therein lay the problem,” said Environmental Sciences Professor Stephen Simpson, one of the lead researchers from the School of Life and Academic Director of the Charles Perkins Centre.

As a result of increased competition for transportation to the brain, serotonin levels in the brain were lowered, which increased appetite in the mice.

“The serotonin decrease caused by excess BCAA intake led to massive overeating in our mice, which became hugely obese and lived shorter lives,” Simpson said.

There were four groups of mice in the experiment: one group of mice was fed double the normal amount of BCAAs, one was fed the standard amount, one was fed half, and one was fed one fifth the normal amount for life. The mice that were fed double the normal amount  increased their food intake, which resulted in obesity and a shortened lifespan.

Instead, eat a variety of protein

“What this new research has shown is that amino acid balance is important – it’s best to vary sources of protein to ensure you’re getting the best amino acid balance,” said Dr. Samantha Solon-Biet, the other lead researcher and a professor at  the University of Sydney’s Charles Perkins Centre.

Dr Rosilene Ribeiro, a dietitian and public health nutritionist from the University of Sydney’s School of Life and Environmental Sciences, recommends eating a wide-range of proteins instead of reaching for a protein bar after a workout.

By varying protein sources, you get a variety of essential amino acids through healthy foods that are rich in fiber, vitamins, and minerals.

Here is a list of protein-containing foods that you can get BCAAs from:

  • Red meat
  • Dairy
  • Chicken
  • Fish
  • Eggs
  • Beans
  • Lentils
  • Nuts
  • Soy proteins

Jennifer Fabiano is an SEO reporter at Ladders.