Are Pure-Protein Meals and Ketogenic Diets Good for Athletes?


We’ve all come across them before. The guy pounding back a huge protein shake on a belly full of scrambled eggs and bacon. The girl heading home from an intense game or practice only to feast upon nothing but chicken breasts and grass-fed beef for the rest of the day. The pure-protein athletes.

This protein obsession has a foundation in nutritional science. It’s very well known that serious athletes in serious athletic training need more daily protein than non-athletes. This means more protein in pre- and post-workout meals, but more protein during the rest of the day as well, as the body is in a constant state of repair from intense workout sessions. But for those who think that protein is the only macronutrient needed to sustain optimal performance—and that the more protein you eat, the faster you will grow lean muscle tissue—you are strongly mistaken.

While protein is a definite must for the athlete, your post-workout recovery meal, along with all the other meals you take in throughout the day, must contain far more than just protein.

Pure-protein meals and ketogenic diets—which contain lots of protein and fat but little to no carbohydrates—are “out” for athletes. Let’s take a look at why too much protein can actually hinder you from achieving your athletic performance goals.


The Body Can Only Use So Much Protein At Once

First, it’s important to remember that your body can only use so much protein in any given day. So many athletes get hooked on the idea that the more protein they consume, the more muscle they will build.

Not so.

The human body can only generate (create) a certain amount of muscle tissue at a given time—any protein consumed over and beyond the body’s muscle-building requirements will simply get used for energy or converted into body fat.

Yes, you read that correctly: excess protein can be stored in the body as fat. It’s testament to the adaptability of the human body to survive in any nutritional circumstance.

Protein then becomes a very expensive source of fuel, because it takes the body great effort to break it down into usable glucose for energy. You will be far better off simply eating more carbohydrates for glucose after your protein needs are met for the day. Your body is going to figure out a way to get glucose—whether it has to create it laboriously from protein or not—so you might as well give your body what it needs.

Too Much Protein Places Strain on the Body

The second reason why athletes should avoid protein-only meals and ketogenic diet plans is because consuming too much protein places a lot of strain on the body.

It is not uncommon to see athletes taking upwards of 2 grams of protein per pound of body weight per day (that’s 300 g of protein for a 150-lb athlete, equivalent to eating 7 chicken breasts), with all the protein shakes, eggs, and chicken breasts they consume—and this is just plain overkill.

Now, if you are an athlete training for a performance goal you do need more protein per day, and a higher protein intake is definitely acceptable. But consuming way too much protein will place a lot of strain on your kidneys, may lead to dehydration (not great for athletic performance), and won’t make you feel very good in general.

While you do have to consume a very high amount of protein for it to be truly harmful for your body, if you are eating a protein-only diet you will come close to doing so. There’s really no benefit to ever taking protein up to 2 grams per pound of bodyweight—or even close to that—so no one should be regularly consuming this much protein.


High-Protein Diets Can Cause pH Imbalances

Source: Sukrin UK

Source: Sukrin UK

Another issue that can arise from too much protein in the diet is potential pH imbalance. Foods can either raise or lower your body’s pH levels, based on the mineral content of the food consumed. In order for the body to function optimally, you need to avoid being in a very acidic state (very low pH). Low pH is not only harmful to athletic performance but can also set you up for serious health concerns, such as bone loss, high blood pressure, suppressed immune system function, and increased risk of vascular and cardiac damage, to name a few.

Adding some alkaline foods (high-pH foods) into your diet—like fresh fruits and vegetables—will help to keep your body in better overall balance so that you can sidestep these pH problems.

Carbs and Fats Are Fuel

Now that we’ve established that too much protein is unnecessary and potentially harmful for your body, let’s talk about the role that carbohydrates and fats play in the diet: they are fuel for your body! As an athlete in training, you need fuel (and the right kind of fuel) to perform your best—and protein is simply a very bad, inefficient energy source.

Picture it like this: you’re a luxury car. You’re getting prepared to hit the road for a long day of high-speed driving. Would you put low-grade gas in your engine? Of course not! You want the best performance possible, and to be able to drive for a long time before stopping to refuel.

If you are an athlete consuming protein alone, you’re using low-grade fuel. Carbs and fats provide high-grade fuel, so they need to be added into your diet. Carbohydrates provide a faster fuel source that can be used immediately for intense exercise (think sprints and weightlifting), and fats provide a longer-lasting fuel source that can be used for longer periods of time (think running long distances or lasting a full game). Both are key to athletic success.

Balance is the Key to an Athlete's Diet

Finally, remember that each of the three macronutrients—proteins, carbs, and dietary fats—will also provide certain vitamins and minerals that you must be taking in if you want to experience optimal health.

While performing great is one thing, achieving excellent health should also be a priority in any diet. If your diet lacks balance, you could be risking vitamin or mineral deficiencies, which could set you up for longer-term health problems and serious issues that would make training virtually impossible.

So, avoid a protein-only diet. Pure-protein meals and ketogenic diets are OUT for athletes—and balanced nutrition is IN.

Make sure that you are making healthy food choices and getting the most from the meals you’re eating, so that you can perform optimally and see great post-workout recovery!

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Mike Bewley, MA, CSCS, C-SPN, USAW-I is a guest contributor to the Volt blog. He is a Strength and Conditioning Coach at Clemson University, a specalist in sports nutrition, and the founder of online nutrition platform NutraCarina.