What happens to excess protein you consume that’s not used for building muscle, is it just stored as extra fat?

In a previous article I have discussed the minimum dose of protein required to maximally stimulate protein synthesis and enhance muscle growth, but the question still remains; what happens if you eat too much protein all at once? Is too much protein detrimental?

If you want to find out what happens with excess protein you eat, you need to read this article...

“The Muscle Full Effect”

Dietary protein has a great ability to stimulate muscle protein synthesis and contribute to muscle hypertrophy. However, it is not a linear relationship where more protein will always lead to a greater synthesis of muscle.

There is indeed a maximum amount of protein your muscles can incorporate into muscle proteins at one time, at which point all the remaining dietary protein will have to find something else to do. This elusive target is quite controversial and heavily debated, but the research for the average man puts it at about 30 grams of protein.

Of course, you may not be the average man. You may have more or less muscle mass than the average man. You may have muscle enzymes that operate at a different capacity than average. Interindividual variability is not a novel concept, it’s just that research has the most global impact when focused to the average.

The truth is that there is no research that directly relates to you as an individual. For this reason, you may purposefully consume above 30 grams of protein at one time just to cover your bases, but when the muscle is full and will no longer synthesize muscle proteins, what happens to the rest of your dietary protein?

Other than being a substrate for muscle growth, protein is still just another macronutrient, and like all macronutrients, if you consume excessive amounts than the body uses, the body will store the leftovers as fat. However, there are a few other uses that the amino acids from dietary proteins have before they may be converted to fat.

1) Cells, Organs & Immune System

The primary way your body stores the amino acids is in the form of muscle protein. However, if you have surpassed the limit that can be synthesized into muscle protein the surplus of amino acids need to go elsewhere. Amino acids are needed for more things than just muscle.

Amino acids can be synthesized into plasma proteins, and other cellular proteins in all other organs and tissues. Every single cell in your body requires amino acids to make receptors, enzymes, and all sorts of other proteins.

The immune system uses amino acids to produce immunoglobulins which is why you should consume more protein when you are sick. However, these too will have a limit to how much protein can be synthesized.

2) Oxidation

Unfortunately, protein cannot be stockpiled for a later time so the next step is to increase amino acid oxidation, which means burning amino acids for energy.

A 2014 study in the American Journal of Clinical Nutrition looked at 4 doses of protein intake: 0, 10, 20, and 40 grams of whey post exercise. In agreement with several other studies, 40 g of protein was in excess than what is needed to maximally stimulate muscle protein synthesis. Coincidentally, the 0, 10 and 20 g of whey protein did not significantly change the rate of amino acid oxidation.

However, ingestion of 40 g of whey protein stimulated a dramatic increase in amino acid oxidation suggesting that a bulk of excess amino acids are simply burned as energy when consumed in amounts greater than what can be synthesized into tissue proteins.

This of course assumes that there is an energy demand. As long as your body is still looking to burn calories, those calories can come from the excess protein from your diet.

It would be incorrect to assume however, that all additional protein would simply be burned if your body isn’t metabolically active in some way above rest.

3) Carbohydrates / Glycogen

Still before fat production, the excess amino acids that are not synthesized into protein and are not oxidized into energy, will be converted into carbohydrates to be stored as glycogen. This can occur through a process called gluconeogenesis that can use amino acids as a substrate and then produce glucose.

The glucose can then be synthesized into glycogen for storage, assuming those stores aren’t already full too.

Therefore, those with a low carbohydrate diet, will have additional capacity for protein than others. There is certainly an added benefit for consuming extra protein post-exercise since glycogen replenishment has a major impact on muscle and performance recovery.

4) Fat For Last

This article isn’t to imply that excess protein can not be converted to fat, because of course it can.

Just like any caloric surplus, if you are consuming more calories than you are burning, then the laws of physics will tell you that you have to gain weight. A caloric surplus with protein doses around the 30 gram range multiple times a day may contribute to fat free gains.

However, if you are consuming excessive protein doses with a caloric surplus, those excess calories not being contributed to lean body mass, can only be contributing to increased fat mass. So, it’s important to watch total calories in addition to total protein at one time.

The Bottom Line on Excess Protein

I encourage making sure you get the most out of your protein supplements. It’s possible that 30 grams of protein for you doesn’t elicit the maximum rate of muscle growth as it does for the average man. So, consuming a little bit extra should not be an issue.

Timing excess protein consumption to after exercise is the safest strategy where the protein overflow can be contributed to oxidation and glycogen recovery rather than fat. So if you do want to load up on your protein, post-workout would be the best time.

If you’d rather not worry about all the little details of your diet, like what to eat when and how much of each to eat, then check out CHISELED365™, a done for you step-by-step program that ensures you know exactly what to eat when and adjusts to your daily progress to get your the best results possible.

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Atherton PJ, Etheridge T, Watt PW, Wilkinson D, Selby A, Rankin D, Smith K, Rennie MJ. Muscle full effect after oral protein: Time-dependent concordance and discordance between human muscle protein synthesis and mTORC1 signaling. Am J Clin Nutr. 92; 1080-1088, 2010.

Witard OC, Jackman SR, Breen L, Smith K, Selby A, Tipton KD. Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. Am J Clin Nutr. 99; 86-95, 2014.

Witard OC, Wardle SL, Macnaughton LS, Hodgson AB, Tipton KD. Protein Considerations for Optimising Skeletal Muscle Mass in Healthy Young and Older Adults. Nutrients. 8; 81 doi:10.3390/nu8040181, 2016.