It’s debatable which of the three macronutrients is most misunderstood. We’ve all heard faulty statements like this:
“Low carb diets are bad because the brain needs at least 130 grams of carbs a day to function.”
“Limit your saturated fat intake because it will increase heart disease risk.”
“Animal protein causes cancer and should be replaced with plant-based proteins.”
Either way, there are many aggravating and dangerous things people say about protein. For example, this article highlights the terrible journalism that fuels many of the most pervasive and harmful misconceptions people have about nutrition.
This is misleading since eating high-quality protein within the context of an overall healthy diet is one of the smartest things you can do for health and longevity.
Not only is a high-quality protein intake that is double the U.S. RDA associated with better maintenance of lean mass during aging, but it is linked with less abdominal belly fat— a primary predictor of heart disease and other heath problems like cancer.
In order to set the record straight, here is the truth behind some of the most annoying and dangerous things people say about protein.
#1: It Hurts Your Kidneys
There is no evidence that eating a high-protein diet damages healthy kidneys. This misconception comes from the fact that in people with chronic kidney disease, high-protein intake can further compromise kidney function, but these are people whose kidneys already aren’t working well.
In people with healthy kidneys, a high-protein intake is perfectly healthy. A study that assessed kidney function in a mix of athletes who were eating between 1.5 and 2 grams per kg of bodyweight of protein a day showed no evidence of impaired kidney function. The researchers concluded that daily protein intake as high 2.8 g/kg is safe for kidneys in healthy athletes.
Even in people who are “at risk” to suffer kidney disease, such as diabetics or the obese, a high-protein diet doesn’t damage the kidneys. One study compared the effect of either a low-carb, high-protein diet or a low-fat weight loss diet on kidney function over two years in obese subjects. Both diet groups lost weight and kidney health was improved due to the loss of body fat since obesity compromises kidney function.
The Bottom Line:
A high-protein intake is perfectly safe for people with healthy kidneys.
#2: It’s Bad For Your Bones
A high-protein intake is consistently associated with stronger bones, not weaker ones. In fact, in one analysis, a high protein intake was associated with greater bone density in several skeletal sites including the lumbar spine in every category of the population, from children to elderly men and women.
This misconception comes from the fact that a diet high in animal protein is associated with an increase in calcium in the urine. But this doesn’t mean that bones are getting weaker. Rather, bone is made up of over 50 percent amino acids from protein, which is one reason that a high protein intake is linked to stronger bones. Additionally, animal protein contains a lot of phosphorus, which mitigates loss of calcium from bone, resulting in better bone density.
Finally, muscle mass, which is improved with a high-protein intake, is correlated with bone density and overall functional strength.
The Bottom Line:
Consuming a higher protein intake within the context of a healthy diet will help you get the amino acid building blocks you need for strong bones.
#3: You Get Bad Breath
The bad breath that people refer to is actually in response to something called “ketosis,” which has nothing to do with a high-protein intake. Ketosis occurs as a result of a low-carb, high-fat diet when the body stops relying on glucose as a primary energy source and starts to burn a byproduct of fat called ketones.
Ketosis can lead to a fruity smell to the breath from acetone, a ketone body that often reminds people of nail polish remover. For many people, the ketosis smell will go away as the body adapts to burning body fat. If you are on a low-carb, high-fat diet and you’re worried about the ketosis smell, chewing mint, ginger, or citrus have all been reported to help.
The Bottom Line:
Ketosis has nothing to do with protein and it is not the same as the bad breath that is associated with gum disease or gingivitis.
#4: It Causes GI Issues
The belief that eating a lot of protein leads to GI problems is due to the faulty belief that a high-protein intake means that you’ll have a low-carbohydrate intake with lack of fiber. However, this is not a given: If you eat vegetables at every meal (as is recommended to promote satiety and consume a healthy dose of antioxidants and nutrients), you’ll easily consume sufficient fiber to avoid any GI problems associated with a low-carb intake.
It should also be noted that it’s completely possible to have a high-carb intake and still by abysmally low in terms of your fiber consumption: The average American consumes less than 50 percent of the already low 25 grams of fiber recommended by the USDA, while clocking in at an average carb intake of 50 percent of calories with protein only making up an average 15 percent of calories.
The Bottom Line:
Always plan meals to include vegetables and you won’t need to worry about GI issues regardless of the amount of protein you consume.
#5: You Gain Weight
We have no idea what study the Fox News article is referring to (maybe they made it up?), but evidence doesn’t support the theory that people who eat more protein will gain weight.
First, it’s important to note that there’s a difference between “weight” (includes body fat and lean tissue like muscle and bone) and “fat,” which is what anyone in their right mind cares about when discussing body composition.
Second, recent studies show that when people increase protein consumption without cutting calories, they are very unlikely to gain body fat. For example, a study that had subjects increase their protein intake by roughly 800 calories a day resulted in no significant change in body weight or body fat (subjects actually decreased body fat by an average of 0.3 kg—an amount that was so small it was deemed insignificant).
A second study that tested the effect of increasing protein intake by 400 calories a day in conjunction with a training program found that subjects lost an average 1.6 kg of body fat and gained 1.6 kg in muscle, ending with the same body weight as when they started.
The Bottom Line:
There’s no evidence to support the theory that eating protein leads to fat gain.