The Top 6 Myths About High-Protein Diets And The Facts Behind the Fiction
For years, outside of the sports nutrition community, protein’s importance was overlooked as the debates about nutrition focused on carbohydrates and fat.
More recently, higher-protein intakes have been shown to be very powerful for supporting weight management programs. They seem to play a role in improving a number of other health outcomes as well, but there are still a number of myths surrounding higher-protein intakes.
The following are six of the most common high-protein myths I still come across. Now you’ll know the truth behind these myths.
1. You can only use 30 grams of protein in a meal
As it relates to maintenance or development of lean body mass, protein both increases protein synthesis and decreases protein breakdown. The more you can increase protein synthesis and/or decrease protein breakdown, the more lean body mass you can build.
Protein synthesis is maximally stimulated after consuming 20-30 grams of high-quality protein. But research shows that protein breakdown is further reduced at higher levels.
A study published in the journal Clinical Nutrition addressed this 30-gram-per-meal myth.[i]
First, the researchers found that when individuals consumed 80% of their daily protein in a single meal, it caused a greater overall anabolic response for the day than when the protein was split up over several meals. This could be because the total protein intake for the day wasn’t excessively high.
Second, they found that the greater the amount of protein individuals consumed, the greater the overall anabolic response was. Greater protein intakes in a meal caused protein breakdown to slow even more. Clearly, the higher amount of protein from a meal was digested and absorbed, and it had a greater impact than a lesser amount, such as the often espoused 30-gram recommendation.
There is a likely a cap at which the total protein intake for the day reaches a limit on its anabolic effect. It’s probably closer to the “one gram per pound body weight” often recommended by sports nutritionists. Split that up over 3-4 meals, and you’ll need to eat a lot more protein than just 30 grams with each meal.
2. Excess protein just turns to fat
To be clear, we’re talking about pure protein. Often, when people envision protein, it’s protein-rich foods like meat, poultry, fish, and dairy. You can’t get away with eating as much filet mignon, cooked in butter and topped with crabmeat and hollandaise sauce as your stomach can hold. There’s a lot more in such a meal than just protein.
However, assuming carbohydrates and fat are kept in check, it seems that eating more and more protein has virtually no effect on fat gain. After a certain point, it doesn’t help in adding more lean mass either.
To test the effects of a super-high protein diet, Dr. Jose Antonio and his team studied two groups of resistance-trained men and women. One group followed a diet that included 1.0 gram of protein per pound of body weight. The other group doubled that amount, eating 2.0 grams of protein per pound of body weight. That’s a lot of protein!
It would be nearly impossible to eat such large amounts from whole food, so a large amount of the extra protein came from protein shakes. This also helped minimize the introduction of additional carbohydrates and fat.
The second group ate an average of 145 grams of protein extra per day and did not gain any weight. Also, they did not eat less carbohydrate or fat. That’s right. They ate 145 grams more protein than the other group and didn’t gain weight. In fact, they averaged about 800 calories more than their maintenance level and didn’t gain body fat. They also didn’t gain any extra muscle from that much more protein. It’s a good example of why You Can’t Count on Calorie-Counting for Weight Management.
Eating too much protein-rich food, with all the fixings and side dishes will surely pack on the pounds, but excess protein itself isn’t a cause of fat gain.
3. Too much protein is hard on the kidneys
One of the byproducts of protein digestion is urea. Urea is filtered by the kidneys, so the theory is that as protein intake goes up, urea goes up which puts an excessive load on the kidneys. While it’s true that urea increases, there is not evidence to show that it’s bad for those with healthy kidney function.
After two years of tracking participants on either a higher-protein, low-carb diet or a lower-fat, low-protein diet, those who ate a higher protein diet experienced no negative impact on kidney health.[ii]
Another study followed three groups over two years. They followed a low-fat, a Mediterranean, or a higher-protein, low-carb diet. After two years, there was no difference in kidney function for any of the groups. The participants were moderately obese individuals, some of who had type II diabetes and some of whom did not.[iii]
Those with a pre-existing kidney issue may need to limit protein intake, but for those with healthy kidneys, evidence suggests higher protein intake is fine.[iv]
4. High protein diets decrease bone density
Just as higher protein intakes help maintain or even increase muscle tissue, they also support greater bone density. High-protein diets do not leach minerals from bone and decrease bone density. To the contrary, they’ve been shown to enhance mineral reabsorption and increase bone density. The greater issue when it comes to bone density is taking in enough calcium, magnesium and vitamin D to support good bone health.[v],[vi]
Women are more likely to follow a low-calorie diet, which is often low in protein. Low protein diets, rather than high-protein diets can contribute to decreased bone density.[vii] Women are already more prone to bone density loss as they get older, so adding a low-protein diet to their lifestyle could accelerate the loss of bone density. The importance of higher protein intake should be stressed to support optimal bone density.
5. Too much protein raises insulin and increases fat storage
Protein consumption does cause a small rise in insulin levels. Insulin is necessary to help shuttle amino acids into muscle cells. The rise in insulin is nowhere near the rise that carbohydrates cause, but protein does cause a rise in insulin.
If someone is following a ketogenic diet as part of cancer therapy, to enhance endurance performance or to address significant blood sugar regulation issues, a higher-protein intake may temporarily take him or her out of ketosis.
For most people, even those with type II diabetes, the increase in insulin from protein is not significant compared to the benefits of the higher-protein intakes. If there was an issue, we would not consistently see the improvements in metabolic syndrome and type II diabetes that we see in research using higher-protein diets.
6. You only need the RDA for protein, which is 0.36 g/lb per day.
The recommended daily allowance (RDA) for protein is amusingly small: 0.36 grams per pound body weight.
For a 150-pound adult, that would be 55 grams per day, about 8 ounces of lean meat.
While such a paltry amount of protein might be enough to sustain life, it’s certainly not enough to have achieve optimal levels of health and fitness, or to achieve a superior level of quality of life.
As Bosse and Dixon stated in their JISSN paper:
The “lay” recommendation to consume 1 g protein/lb of bodyweight/day (2.2 g/kg/day) while resistance training has pervaded for years. Nutrition professionals often deem this lay recommendation excessive and not supported by research. However, as this review shows, this “lay” recommendation aligns well with research that assesses applied outcome measures of strength and body composition in studies of duration > 4 weeks.[viii]
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[i] Deutz NE, Wolfe RR. Is there a maximal anabolic response to protein intake with a meal? Clin Nutr. 2013;32(2):309-313
[ii] Friedman AN, Ogden LG, Foster GD, et al. Comparative Effects of Low-Carbohydrate High-Protein Versus Low-Fat Diets on the Kidney. Clin J Am Soc Nephrol. 2012;7(7):1103-1111
[iii] Tirosh A, Fiedler GM, Golan R, et al. Renal Function Following Three Distinct Weight Loss Dietary Strategies During 2 Years of a Randomized Controlled Trial. Diabetes Care. 2013;36:2225-2232
[iv] Martin W, Armstrong L, Rodriguez NR. Dietary protein intake and renal function. Nutr & Metab. 2005;2:25
[v] Heaney RP, Layman DK. Amount and type of protein influences bone health. Am J Clin Nutr. 2008;(suppl):1567S-70S
[vi] Cao JJ, Johnson LK, Hunt JR. A Diet High in Meat Protein and Potential Renal Acid Load Increases Fractional Calcium Absorption and Urinary Calcium Excretion without Affecting Markers of Bone Resorption or Formation in Postmenopausal Women. J Nutr. 2011;141:391-397
[vii] Bonjour JP. Dietary Protein: An Essential Nutrient for Bone Health. J Am Coll Nutr. 2005;24(6):526S-536S
[viii] Bosse JD, Dixon BM. Dietary protein to maximize resistance training: a review and examination of protein spread and change theories. JISSN. 2012;9:42