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. 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. The dietary guidelines recommend about 15% calories come from protein.
The term “high-protein diet” is often used to describe a diet of about 30% protein.
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.
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.
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.
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
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.
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.
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
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.
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.
The quality of proteins, and the amount per serving, in vegetable foods and animal foods is dramatically different.
Are there other reasons people have told you to limit your protein intake? Share your thoughts or comments below.