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Sports Nutrition

High-Protein Diets Debunked

If you found out that something you were eating caused heart disease, kidney disease and osteoporosis, you’d swear off it, right? What if we told you that protein is the fiend accused of all these bad things? Any casual reader of “health” blogs or follower of mainstream nutritional dogma (even much of that conjured up by conservative government types and swarms of investigators who are cloistered away in their pursuit of scientific discovery) could be forgiven for thinking that protein is dangerous and that getting too much of it can undermine the very goals you’re eating it to achieve.

However, before we all panic, the critical fact here is that research doesn’t actually prove the link between high-protein diets and any of the above diseases, particularly not in athletes. What all the naysayers tend to have in common is their focus on the average American, that overweight couch potato whose favorite foods are fatty, sugary, fried, greasy or some unholy combination thereof.

We’re going to go out on a limb and assume that you are not an average American. Happily, athletes are not the norm, and the research proves that bodybuilders and athletes need more protein than the average American. Read on to learn how these vicious rumors got started in the first place and to see the truth about high-protein diets in athletes.

Q: What constitutes a high-protein diet?
A: Somewhere between 1 and 2 grams of protein per pound of bodyweight per day.

This topic can be a bit touchy for many nutritionists, who are honor-bound to follow the mainstream rules of the Institute of Medicine. In 2005, an expert Institute of Medicine panel published the Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Buried in the depths of this 1,357-page tome is the recommendation that all men and women consume 0.8 grams of protein per kilogram (about 0.4 grams per pound) of bodyweight on a daily basis. And this is the standard answer most nutritionists will give when asked how much protein any one person needs in a day.

So, for a guy who weighs 180 pounds (81.8 kilograms), that would be about 65 grams of protein per day. To give you an idea of how much food that isn’t, our hypothetical 180-pound guy supposedly gets enough protein for the day after eating a cup of 2 percent cottage cheese (27 grams of protein) and a half fillet of salmon (39 grams of protein). Forget about the three eggs for breakfast, that chicken sandwich at lunch or the protein shakes before and after the gym.

The good news is that these recommendations are meant to be general and apply to the average American. Even before the Institute of Medicine publication, experts had come to the conclusion that physically active folks need more protein than the average Joe (duh!).

Dr. Peter Lemon, writing in the October 2000 issue of the Journal of the American College of Nutrition, advocates that athletes should consume 1.6 to 1.8 grams of protein per kilogram (0.7 to 0.8 grams per pound) of bodyweight each day. In 2009, the American Dietetic Association, Dietitians of Canada and the American College of Sports Medicine issued an updated joint position statement regarding exercise and optimal nutrition. They note that athletes should consume 1.2 to 1.7 grams of protein per kilogram (0.5 to 0.8 grams per pound) of bodyweight per day. Meaning that a 180-pound gym-goer should be eating 90 to 144 grams of protein every day. That’s at least closer to our recommendation that you should be consuming anywhere between 1 to 1.5 grams of protein per pound per day.

Q: Will following a high-protein diet cause heart disease?
A: No, so long as you’re eating the right protein and not skimping on whole grains or fresh fruits and veggies.

The argument from the American Heart Association, which doesn’t recommend high-protein diets for weight loss, is that many diets, a la Atkins, tend to restrict carbs, including high-fiber and nutrient-dense foods like whole grains and fruit. This can limit vitamin and mineral intake and therefore increase the risk of heart disease.

Another concern is that high-protein diets can be high in saturated fat from red meat, whole-fat dairy products and other high-fat foods. Science has shown that a diet high in fat also raises the risk of heart disease.

The truth is that it’s the fat that has the American Heart Association concerned. In its discussion of high-protein diets, the association recommends dieters eat a max of 35 percent of total calories from fat, less than 7 percent from saturated fat and less than 1 percent from trans fat. It stands to reason, then, that so long as a high-protein diet includes low-fat sources of protein (such as lean beef, fish, chicken, soy, legumes and low-fat dairy), this risk factor isn’t a problem. In fact, 2004 research out of Arizona State University showed that a high-protein, low-fat regimen helped dieters lose weight and lowered their cholesterol, which happens to reduce the risk of heart disease.

Plus, consider this: In order to maintain total calorie intake, higher-protein diets have to be lower in carbs. And that seems to be the key to protecting heart health. In a 2005 issue of the journal Nutrition & Metabolism, protein researcher Jeff Volek, Ph.D., reported that adding saturated fat while removing carbs from the diet lowered triglyceride levels and raised levels of good cholesterol (HDL) in the blood. He also stated that the type of saturated fat found in meat has not been shown to increase levels of LDL, or bad cholesterol. This research suggests that it’s not dietary saturated fat intake that’s responsible for heart disease, making it that much easier to follow a higher-protein, lower-carb diet.

Q: Will following a high-protein diet cause osteoporosis?
A: Nope.

The theory behind the warnings that a high-protein diet will cause osteoporosis is that these types of diets make the body ditch calcium. In all honesty, those who eat a meatalicious diet do have higher urinary calcium concentrations than those who don’t, but the research has failed to show any link between high-protein intake and bone disease.

In a 2003 issue of The Journal of Nutrition, researchers noted that no study has definitively proved that a high-protein diet, and the corresponding increase in urinary calcium, is a detriment to bone health. On the other hand, the series of studies did show that consuming a diet low in protein affects intestinal calcium absorption and could hurt bone health.

More recently, a 2011 report in the same journal showed that post-menopausal women — a group already at an increased risk of osteoporosis — on a high-protein diet did not exhibit changes in markers of bone health, except the expected rise in urinary calcium. The researchers concluded that a high-protein diet has no adverse effects on bone health.


Q: Will following a high-protein diet cause kidney disease?
A: Not likely in healthy individuals, although there seems to be a risk of worsening kidney disease in those who already have it.

The arguments around this high-protein cautionary tale are similar to those for heart and bone health: High-protein diets affect metabolic markers. With regard to renal function, high-protein diets appear to chronically increase glomerular pressure and hyperfiltration, both of which have to do with how urine is formed in the kidneys.

These changes are likely normal adaptive mechanisms that are “well within the functional limits of a healthy kidney,” researchers at the University of Connecticut reported. They published a literature review in 2005 in the journal Nutrition & Metabolism, noting that there is no significant research showing a link between 2 grams or more per day of protein per kilogram of bodyweight and the onset of kidney disease in healthy people, particularly physically active people.

Resistance training actually stymies changes in renal function, according to a 2010 animal study in the British Journal of Nutrition. The researchers also said that evidence suggests individuals with chronic kidney disease who eat a higher-protein diet can actually speed up kidney deterioration, but there’s no proof to show that eating a diet high in protein harms kidney function in healthy people.

Consuming as much as 2.2 grams of protein per kilogram of bodyweight (almost 5 grams per pound) per day has no negative effects on kidney function, according to a report in the December 2010 issue of Nutrition Journal. For the study, overweight subjects used protein meal replacements as part of a yearlong weight-loss program, and they exhibited no negative changes in kidney, liver or bone markers.

Q: What are the implications for following a high-protein diet long term?
A: Likely minimal.

Those overly cautious dietary powers that be persist in worrying that for that lazy, overweight average American, long-term high-protein diets may lead to heart and kidney disease and osteoporosis. This is primarily because published research typically examines short-term (four week to six month) diets, and those studies that have lasted longer than six months didn’t show continued weight loss. Which of course leads researchers to conclude that they shouldn’t be followed for longer than that time.

But we’ll say it again. Athletes are different. Major dietary organizations concede that athletes need more protein than your typical American, and research has shown the muscle-building benefits of increasing dietary protein. Basically, nutrients, even in higher quantities, aren’t dangerous as long as the body uses them. Those with more muscle mass or more intense workout regimens need that protein to maintain and grow muscle. So as long as you keep hitting the gym, you can keep protein high on your dietary list.

SIDEBAR: A Day in the (Protein-Full) Life

So now that it’s clear that eating a higher-protein diet is not going to endanger your health, how do you go about creating one? The starting point is always the protein. If you make it the central point of every meal, then you’re well on your way.

What follows is a sample one-day meal plan for a 180-pound man. You’ll see that protein figures prominently in every meal and that it comes from a variety of sources, from the once-dreaded eggs (which can no longer be criminalized because research shows that eating them doesn’t affect cholesterol levels) and lean steak to protein powders.