How Much Protein Do You Need

Demystifying the Science Behind High-Protein Diets

One of the most contentious debates in the fitness world is protein intake—specifically, how many grams of protein you should consume each day. The typical internet fitness expert recommends anywhere from 0.5 grams of protein per pound of body weight (lowest) to 2 grams of protein per pound of body weight (highest), which is well above the USDA's recommendation of 0.36 grams of protein per pound of body weight. So, you might ask, who's right?

With questions like these, the answer is often closer to it depends than a simple, easy-to-understand number, but it's still worth getting a good estimate of your body's needs, as optimizing your protein intake is a solution to many common health issues and a great way to build muscle, fight fatigue, and even keep your brain functioning at a high level.

Everything You Need to Know About Protein Intake

Protein is one of those important macronutrients, and whether you want to eat more or less each day, it's worth understanding its role in the body.

What Are the Benefits of Protein?

In the popular imagination, protein intake and muscle mass go hand in hand. Want to look like Arnold? Eat more protein, bro! This connection exists because your body breaks down protein into amino acids, which it then uses to repair damaged muscle tissue. Not consuming enough protein can impair this process. But protein has more benefits than just maintaining and building muscle, like:

Increases bone density: Higher protein intake has been shown to promote improved bone density and protect against osteoporosis, which only becomes more important as you age since bone density tends to decline over time.

Lowers blood pressure: In a recent meta-analysis of the effects of protein intake on health, a link was established between high-protein diets and decreased systolic and diastolic blood pressure. Even better, another major study conclusively dispelled the purported link between high protein intake and heart disease, so you can put that worry to rest, too.

Delays in cognitive decline: A notable study in the American Journal of Clinical Nutrition examined diet and long-term health outcomes in more than 77,000 men and women and found a positive correlation between a high-protein diet and long-term cognitive function. Specifically, for every 5% increase in protein intake relative to carbohydrate intake, there was an 11% lower risk of dementia.

Improved Skin Elasticity: Aging may be inevitable, but that doesn’t mean we want to look old. Thankfully, there’s a proven link between a high-protein diet and improved skin elasticity, preventing wrinkles and fine lines and keeping your skin youthful as you age.

If it’s not obvious yet, let’s get this straight: protein intake is about more than just muscle mass, optimizing your protein intake has all sorts of benefits for your overall health and well-being.

What are the signs of a protein deficiency?

There’s a lot of debate about the upper limits of protein intake, but there’s little disagreement about the dangers of protein deficiency. In other words, while reasonable people may disagree about the upper limits of protein intake, these same people can all agree that consuming too little is a disaster for the body. If you suffer from a protein deficiency, you may experience some or all of the following symptoms:

• Chronic fatigue
• Edema (body swelling)
• Thin skin
• Brittle nails
• Thinning hair
• Difficulty gaining muscle
• Chronic colds
• Anemia (decrease in red blood cells)
• Increased hunger

Does the source of protein matter?

Absolutely! One of the problems with research on the health effects of high-protein diets is that not all protein sources are created equal. If you eat fast food burgers for lunch and dinner, you may be hitting your protein goals, but fast food burgers contain far fewer nutrients than, say, grass-fed beef tenderloin (and contain more preservatives, nitrates, and other undesirable additives).

If you need inspiration for quality protein sources, Harvard Medical School offers a great list, including lean meats and fish, beans, peas and lentils, quinoa, eggs, nuts, and seeds. These sources are ideal because they provide not only protein but also a host of other nutrients your body needs to function properly, including vitamins and minerals.

Who Should Eat a High-Protein Diet?

Bodybuilders and other strength athletes need a high-protein diet, but who else can benefit from increasing their protein intake? Multiple studies have shown that a high-protein diet is beneficial for promoting weight loss, first because the protein itself requires energy for the body to break down and use, and second because it promotes satiety (fullness), making it easier to stick to the diet.

There are also certain special cases where pretending to be a bodybuilder can be a big boost: for example, if you are injured, especially if you are bedridden, a higher protein intake can help your body preserve muscle mass and slow or offset atrophy.

Endurance athletes (such as swimmers, cyclists, runners, and rowers) can also benefit from increasing their protein intake, as the effects of prolonged endurance exercise on existing muscle tissue are highly catabolic.

Is Eating Too Much Protein Bad for You?

A long-standing misconception about protein intake is that there is an upper limit to the body's ability to process protein, and exceeding this limit may damage the kidneys. The science on this point has been around for a long time: unless you already have kidney disease, a high-protein diet will not damage the kidneys. For most people, the worst outcome of overeating protein is storing the extra calories as fat, but that's unlikely to happen since protein is hard to overeat compared to carbs.

No More Delay - I Want a Number

Okay, okay, for those of you who don't really care about the why and just want some actionable info, here's the TL: DR. The USDA recommends 0.36 grams of protein per pound of body weight, which may be fine for most men, but is definitely not enough for athletes and anyone trying to gain muscle or lose weight.

If you lift weights regularly if you're looking to build muscle, or if you're over 30% body fat and are dieting to lose weight, start with 0.5 grams of protein per pound of body weight and work your way up from there. Good signs that you're moving in a positive direction by adding protein to your diet include increased energy, faster recovery, and gradual strength gains.