When you ingest amino acids, your body uses them to make enzymes and proteins as needed. Any leftover amino acids follow various metabolic pathways. Some are converted into glucose and used as energy. Others become glycogen and are stored in the liver and muscle for future energy use. And still others are turned into fat and stored in fat cells.
However, should you worry that the amino acid supplement you’re taking is causing weight gain? Let’s explore.
Amino Acids Are Low Calorie
Amino acids contribute 4 calories for every gram of protein you consume. So, 4 grams of an amino acid supplement is only 16 calories. Beneficial effects of essential amino acid supplements have been demonstrated with doses less than 4 grams, so if you’re worried about calorie consequence, then you can supplement with a simple 4-gram, 16-calorie dose.
You also get amino acids from the dietary protein you eat. However, the calorie load from dietary protein is significantly more. Consider this: 4 grams of essential amino acids from a high-quality dietary protein such as pasture-raised meat contributes 100 calories to your daily intake compared to just 16 calories from your amino acid supplement.
When it comes to weight gain, it’s important to monitor the number of calories you’re ingesting with your body’s energy needs. To determine how many calories you should eat each day based on your gender, height, and activity levels, use this online calculator from healthline.com based on Mifflin-St Jeor equation for estimating calorie requirements.
Amino Acids for Fat Burning
Far from causing notorious weight gain, amino acids can help boost the production of hormones that help burn fat. One such hormone is the growth hormone (somotropin, STH). STH activates protein synthesis as well as fat burning. Studies show that obese and overweight individuals tend to have low concentrations of STH. Certain amino acids have been shown to increase levels of STH; most notably, arginine, methionine, and glutamine.
A 2011 study published in The Journal of Nutrition showed that individuals with a higher intake of branched-chain amino acids (BCAAs) had a lower prevalence for obesity or being overweight. The study focused on middle-aged adults from East Asian and Western countries. Researchers attributed the effect to the BCAA leucine, which can increase energy expenditure, as well as the ability of BCAAs to improve glucose tolerance (how well your body processes glucose, or sugar).
So, I don’t think amino acids cause weight gain, unless you are eating an ultra-high-protein diet and not burning off the excess amino acids. I do think amino acids help you maintain and build muscles, which may cause moderate weight gain (muscles weigh more than fat!), but a better body mass index (BMI) and a leaner, more toned figure.