There are numerous health, performance, and longevity benefits of protein. Eating high-quality protein improves sleep, minimizes hunger, increases bone strength, boosts lean mass, and improves metabolic hormone levels.
Eating a diet rich in high-quality protein also increases insulin sensitivity, glucose tolerance, and prevents fatty liver—a disease that is running rampant due to sedentariness and the unhealthy Standard American Diet.
Despite all these valuable benefits, there are certain situations in which a high-protein intake can cause more trouble than it’s worth. This article will give you a heads up on three situations in which a high-protein diet is a bad idea, with alternatives for avoiding pitfalls so that you can optimize your protein intake.
#1: Poor Gut Health
One of the most common problems with a high-protein intake has to do with the gut. We all know about the bacteria that live in the GI tract, regulating immunity, hunger levels, and cognitive function.
Your gut bacteria live off what you eat. People who eat more animal protein tend to eat fewer fruits and vegetables and consume less fiber. In fact, westerners are terrible about fiber intake, regardless of whether they are eating a high protein diet or not, meaning that there are a lot of unhealthy guts out there. Less than 10 percent of Americans reach the American Dietetic Association recommendation of 25 grams of fiber a day and the average American clocks in at around half that amount.
Lack of fiber results in the die-off of protective gut bacteria. Meanwhile, harmful gut bacteria that feed on animal proteins will proliferate. An overgrowth of inflammatory gut bacteria releases metabolic toxins that are linked with adverse health conditions, including cancer, obesity, and type 2 diabetes. This situation is made worse by the fact that most people don’t properly chew their animal proteins. It’s easy to envision that a bodybuilder who eats 10 protein-centric meals a day probably isn’t chewing their chicken breast or steak optimally.
When animal proteins reach the GI tract intact, they not only feed harmful gut bacteria, but they can harm the intestinal wall that protects your body from everything that passes through your gut.
When the intestinal wall becomes more permeable than it should be, waste products and toxins that should be eliminated can escape, producing inflammation. Excessive intestinal permeability is also linked with the development of food intolerances. Amino acids are not supposed to escape the GI tract and be randomly circulating in your blood stream.
When this happens, the body mobilizes an immune response, producing antigens that trigger symptoms, including digestive issues (constipation, flatulence, acid reflux), itchiness or skin irritations, fatigue, depression or brain fog, and weakened immunity. Some people simply feel sick after eating.
Solution: You don’t necessarily have to give up your favorite protein foods to heal your gut. After all, inadequate protein impairs immunity and increases the likelihood of infection and permeability in the gut.
Instead, support the growth of beneficial anti-inflammatory gut bacteria with a diet high in fiber-rich vegetables, fruit, and something called resistant starch, which serves as fuel for protective gut flora. Found in foods such as bananas, oats, peas, maize, potatoes, and supplemental unmodified potato starch, resistant starch consumption is one of the easiest ways to improve your gut bacteria.
Consuming probiotic foods can also help. One study found that regular consumption of the Korean condiment kimchi made from fermented cabbage can counter inflammation in the GI tract and protect against colon cancer via a variety of therapeutic mechanisms. Probiotics can be consumed in a supplement or from other fermented foods such as sauerkraut, kefir, kombucha, and dairy.
Rotating your protein sources is also recommended. A complete overview of food rotation is out of the scope of this article but here’s how it works in a nutshell. Split your diet into four days, eating different foods each day. Let’s say on Day 1 you ate salmon, spinach, eggs, tomatoes, and broccoli (obviously, your diet will be more varied but this is just a quick example). You won’t eat any of those foods on days 2-4, but on Day 5 you can repeat your Day 1 foods.
If you’re not able to rotate all of your foods on a 4-day cycle, do your best to rotate protein sources. If you’re short on ideas, using a different cooking method (for example, scrambling eggs instead of eating them hardboiled) can be helpful. Don't be afraid to include vegetable protein sources, such as legumes and nuts. Rotating your supplemental protein source is also smart. You can alternate between high-quality whey, yellow pea, and rice bran protein or an amino acid blend.
Finally, never consume protein all by itself because this reduces digestibility and increases risk of developing an intolerance. Both dietary fat and green vegetables increase absorption of protein. Many protein sources contain dietary fat, but if you’re eating super lean protein, add a handful of nuts, some coconut or olive oil, or other fat source to protect your gut.
#2: A Disease State—Type 2 Diabetes & Obesity
High-protein, low-carb diets are often the first line of defense to treat obesity and type 2 diabetes because they can produce significant weight loss, while restoring insulin sensitivity quickly. Protein foods also improve blood sugar balance. Additionally, they are great for minimizing hunger when dieting because they lead to the release of gut hormones (CCK, peptide YY, and GLP-1) that give the brain a “stop eating” message.
However, in people who are in a disease state, meaning they have inflammation in addition to obesity or diabetes, a high-protein intake may be harmful. A healthy gut is unlikely—both diabetes and obesity are associated with an increase in harmful gut bacteria—making protein intolerances and the other issues we saw in #1 more common.
This problem is evident in a study in which scientists found that obese patients with chronic gut inflammation were resistant to weight loss in response to a low-calorie, low-carb, high-protein diet. They were also more prone to weight regain once the dietary intervention ended and they went back to eating their normal diets. Researchers theorize that unhealthy gut microbiota affected the subjects’ metabolisms by increasing calorie absorption from food, increasing gut barrier leaking, and fueling systemic inflammation.
It should be noted that inflammation isn’t strictly localized to the GI tract when gut health is compromised. An unhealthy gut can lead to the production of harmful compounds that cause inflammation in other parts of the body. For example, TMAO, a compound produced when gut bacteria feed on certain amino acids, can lead to plaque buildup up in the arteries, raising heart disease risk. With obesity, diabetes, or chronic inflammation your risk of heart disease skyrockets, so you don’t want to make it worse by overloading on protein.
Solution: If you love protein foods—steak, salmon, turkey breast, and scrambled eggs—don’t worry. You won’t need to eliminate them, but you do need to heal your gut and eat an anti-inflammatory diet. Start with the recommendations in #1 and consider incorporating the following:
Eat leafy green or cruciferous (broccoli, cauliflower, cabbage) vegetables with healthy fat at every meal. Green vegetables provide indigestible fiber to feed your healthy gut bacteria along with a slew of antioxidants that help the body eradicate inflammation. The healthy fat (nuts, olive oil, avocado, coconut oil) will improve absorption of nutrients.
Consider going vegetarian for a set time. Depending on the severity of inflammation, opting for more vegetarian proteins (from beans, nuts, seeds, lentils, split peas, etc.) will starve the harmful bacteria that produce oxidative stress. Seafood can often be included as long as you choose low-pollution varieties.
Opt for quality not quantity. Getting the majority of your diet from vegetables, beans, seeds, nuts, and seafood with a small amount of quality animal protein (organic, grass-fed beef and dairy or organic poultry and eggs) will feed your protective microflora and balance the gut.
#3: Stagnation: You’ve Been High–Protein For A Long-Time
There’s a saying, “the best diet is the one you’re not on.”
If you’ve successfully lost body fat or worked with clients on fat loss, you probably noticed that one of the fastest ways to make progress is to switch things up. The body’s response to the macros and calories you eat is not static. Over time, the body begins to adapt to a set calorie intake and macronutrient distribution, modulating metabolic rate in an effort to keep you weight stable.
We see this in countless randomized weight loss trials: Subjects lose body fat initially, but as their bodies adapt, weight loss stalls. More time goes by and most people get tired of dietary interventions, especially low-carb, high-protein ones, and they veer off plan, gaining the fat back.
Stagnation with diet is also evident with muscle gain: One review identified a “protein change” theory. In studies that controlled diet in conjunction with a training program, the most muscle size was gained from studies that had participants change their protein intake from what they normally consumed. In this case, the amount of “protein change” to produce the greatest increase in muscle was a 60 percent increase over habitual protein intake. To see a benefit of protein intake on muscle mass, subjects had to increase their daily protein by at least 20 percent.
Solution: Instead of a “more is always better” approach when it comes to protein, try periodizing your nutrition so that you go high in protein when engaged in intense exercise followed by lower protein intake during recovery or de-loading phases.
Strategically introduce variety into your diet. Your day-to-day nutrition approach should be consistent:
Over the long run, mix things up:
Every two weeks or so, adjust your macronutrient ratios.
Change your calorie intake day-to-day within a 500 to 700 calorie range.
For example, we know that carb cycling (in which you eat a higher carb intake on training days and lower carb on rest days) is an effective tool for overcoming the pitfalls to low-carb diets and can elicit greater fat loss by preventing the adaptations to a low-carb intake. Similarly, modulating calories during fat loss can prevent metabolic adaptation and improve levels of hormones and neurotransmitters that regulate hunger and energy expenditure.
Final Words: Despite the many benefits of protein foods, high-protein diets aren’t robust to faults. There are serious things that can go wrong with them. Use the advice in this article to avoid the pitfalls so that you achieve optimal health and body composition while still enjoying your favorite protein foods.