Higher-protein diets have consistently shown to deliver better weight loss results than low-calorie, high-carb, moderate protein diets. Fitness enthusiasts and body builders have known this for decades. But, even today, some conventional healthcare professionals express concern over increased protein intake.
Often, this isn’t because those healthcare professionals have actually read research to show higher protein intake is bad. Instead, they’re just repeating what they’ve heard from other people they trust, who repeated it from someone else, and on down the line. In reality, higher-protein intake has been shown to be safe and effective for both health and weight management.
In fact, higher-protein diets are probably closer to the way we’ve eaten throughout most of human history. Humans haven’t been eating breakfast cereal with skim milk, chips, pasta, bagels and other starchy foods for very long, relative to the time humans have been on the earth. I find it amusing that the foods that have been around the longest and found in nature are questioned for their health value, and the foods that are new to the diet and made in a factory are deemed healthy.
The dietary guidelines recommend about 15% calories come from protein. That’s actually about how much protein the average American consumes, even though the media loves exaggerating things and suggesting Americans eat a ton of protein. Often, these stories include images of steaks, hamburgers, and other protein-rich foods. Nonetheless, we really don’t eat much of it. Instead, the average American loads up on carbohydrates and added unhealthy fats (the kinds found in processed foods).
The term “high-protein diet” is often used to describe a diet of about 30% protein. This is an important point, as I wouldn’t recommend people just eat protein. So just for clarification, we’re not talking about an all meat diet when we say “high protein.” We are saying a high protein diet includes more protein than the average person eats, which could be part of the reason the average person carries a lot more body fat than he or she should.
5 Myths About Protein Intake
Myth 1: Excess protein is bad for the kidneys
Of all of the myths, the protein-kidneys myth seems to be the one I hear the most medical professionals talk about. This myth got started from research on patients with kidney disease. The kidneys play an important role in protein metabolism. Those with kidney disease have a difficult time processing protein and are often prescribed a low-protein diet. This is an unfortunate circumstance of the disease.
Unfortunately, the medical community made an enormous leap. They saw that patients with kidney disease couldn’t process protein well, so they then jumped to the conclusion that too much protein must be hard on the kidneys. This was a wild assumption.
Suggesting high protein intake is bad in healthy people because it is in those with kidney disease is like saying drinking water is bad in healthy people because it’s bad in those who are drowning.
The myth got started, then research studies were done to see if it was true. Since that time, multiple studies have been done on higher protein intakes, which have found that higher protein intake is completely safe. In the short-term the body adapts to the higher protein intakes which changes some markers of kidney function. This is part of the adaptation process to the additional protein. However, long-term consumption of higher amounts of protein do not have a negative impact on kidney function.[1,2,3]
As the authors of a recent study said,
“In conclusion, this study, the longest and most comprehensive to date on the effects of a low-carbohydrate high-protein diet on renal function, revealed that the diet was not associated with noticeably harmful effects on GFR, albuminuria, or fluid and electrolyte balance compared with a low-fat diet in obese individuals without pre-existing kidney disease.”
Myth 2: Excess protein is bad for bone health
If you speak to a conventionally trained dietitian, he or she may tell you something along these lines: Increasing your protein intake will make your body more acidic. To buffer the acid load, your body will release calcium from bone, making your bones more brittle. If you eat too much protein your body will become too acidic and you’ll lose bone density. Yikes!
Again, this myth is quite a departure from what studies show. In fact, studies consistently show increased protein intake results in greater bone density!
Increased protein consumption results in better calcium absorption. It also increases levels of IGF-1, an important growth factor for bone density.
There is also no evidence to show that vegetable proteins are better for bone health, which seems to be a popular myth as well. In fact, vegetable proteins may be less effective because they often lack some of the amino acids.
A paper in the American Journal of Clinical Nutrition concluded,“…higher protein diets are actually associated with greater bone mass and fewer fractures when calcium intake is adequate.”
Myth 3: Excess protein just turns to fat
I find this myth the most amusing of the five I’ve outlined. Even if you knew nothing about nutrition, you’d probably assume it was quite difficult to turn a piece of muscle tissue into the fat that sometimes surrounds it. Just look at a piece of marbled steak. Intuitively, you’d probably think it would be some kind of magic to turn the red tissue into the white tissue.
You’d be right. It isn’t necessarily magic, but it is a very long and metabolically costly process to turn protein into fat. Protein needs to be broken down into amino acids and absorbed. That process alone burns about five times as many calories as the process of breaking down carbohydrates to glucose. Once the amino acids are available, they can be used for growth and repair or converted to glucose. If they are to be converted, that requires some energy again. The body will turn protein to glucose when necessary, but it prefers not to. If the glucose isn’t needed, it can then be converted to fat.
You can’t turn protein directly into fat. At some wildly excessive point, you might be able to eat so much protein that it could become useless and get stored as fat. However, protein has such a potent effect on reducing appetite, you wouldn’t be able to eat that excessive level on a daily basis. You’d also expend a lot of energy as heat with the excessive protein intake. If you’ve ever let loose at a Brazilian steak house, you know what the meat sweats feel like.
I would also steer clear of any “expert” who suggests too much protein will make you fat as he or she probably believes weight management is about counting calories. In case you missed it, I recently pointed out 9 Reasons Why Counting Calories is Dumb. Can it be overdone? Yes, but you’re probably not listening to your body when it tells you you’re full.
Myth 4: You can only absorb 30 grams of protein in a meal
You can most certainly absorb more than 30 grams of protein in a meal. This idea mainly stems from the fact that studies show protein synthesis peaks following a protein intake of 30 grams. With more protein, there is not a further increase in protein synthesis. However, protein plays a role in other metabolic factors. It also slows protein breakdown, which I discuss in Can I Eat More Than 30 Grams of Protein in a Meal?
There’s also something to be said about the importance of getting enough protein in during a full day. If you only eat two meals in a day, you’d need to eat more protein in each of those meals than if you ate five meals in a day. In fact, it appears you may have a more anabolic effect from eating fewer, bigger meals than more frequent, smaller meals. However, I wouldn’t get hung up on it too much. If you like to eat every few hours and are consistent with eating protein in each of those meals, you can get by with less protein in each meal than if you just eat a couple meals per day.
The bottom line is the 30-grams-per-meal myth is just that, a myth.
Myth 5: Vegetable protein is just as good as animal protein
Just to be clear, I’m not opposed to getting some protein through plant sources. In fact, I had a protein shake with rice/pea protein while I was working on this blog post. However, I would not rely only on plant-based protein sources, especially without using nutritional supplements.
At the beginning of the post, I mentioned that a higher protein diet typically has 30% or more of its calories from protein. Put another way, protein intake is often 1 gram per pound lean mass to 1 gram per pound body weight, depending on one’s body composition. To achieve protein intakes that high without supplementation would be difficult with only plants, unless someone ate an enormous amount of soy. I’ll save that for another day, but I’d keep soy consumption to a minimum.
Aside from the difficulty in getting enough protein from plants alone, most are deficient in certain amino acids. It’s possible to combine them, but it takes some practice. Frankly, other than observational studies comparing one country’s food consumption against another’s, it’s hard to find a reason to recommend plant-based proteins over high-quality animal proteins. I realize this requires at least one, if not more than one, full blog posts to cover in detail.
For now, I just want to point out that the quality of proteins, and the amount per serving, in vegetable foods and animal foods is dramatically different. I’m all for eating plenty of vegetables and fruit each day, but it’s for the vitamins, minerals, fiber and phytonutrients, not for the protein they contain.
Are there other reasons people have told you to limit your protein intake? Share your thoughts or comments below. Thanks for reading.