The Pros and Cons of High-Protein Diets

Are high-protein diets more effective than other diets for achieving weight loss?

High-protein diets have gotten a lot of attention and have been the subject of dozens of studies because of the growing obesity problem in America and its many associated health conditions in the hope that these diets may be a viable approach to addressing these problems. In fact, most research confirms that people who incorporate more protein into their diet while maintaining or restricting calories lose weight.

Protein is heralded as a friend to dieters primarily because it increases satiety (your sense of fullness). One study showed that women who increased the amount of protein in their diet by 15 percent — for a total of 30 percent of daily calories from protein — spontaneously ate fewer total calories.

Another reason eating more protein may contribute to weight loss is because it takes more energy to digest than carbohydrates or fat. It’s also thought that higher protein consumption may help maintain weight loss long-term after successful dieting. The mechanisms by which protein has these effects is the subject of ongoing studies.

In reality, the effect greater protein consumption has on weight loss will depend on the makeup of the rest of your diet. If you are simply adding more protein without making any other changes, you’ll gain weight if you are eating more calories than you use (your resting metabolic rate). The basic truth that to lose weight you have to consume fewer calories or increase your level of activity, or both, hasn’t changed. But if you swap out protein for simple carbs or fat it may be easier to stick to your diet, and initially, other favorable changes may occur.

The terms “high-protein” and “low-carb” are generally interchangeable. Different diets have different formulas, but most operate on the theory that if you restrict carbs — and eliminate the simple and highly processed ones — your body will be forced to burn fat for energy, a state known as ketosis.

Restricting carbs also causes your body to shed excess water, which is a large part of why these diets result in such dramatic weight loss in the first weeks. Eating more calories from protein while dieting can also help preserve lean muscle, the loss of which is a drawback to some other diets.

Potential drawbacks of a high-protein diet

Critics of these diets — including the American Heart Association — argue that they often lead to consuming more animal protein, which can contribute to health risks from increased saturated fat. Severely restricting carbohydrates also reduces essential nutrients and fiber that come from vegetables, fruits, and whole grains. There is also evidence that short-term high-protein diets can place a strain on your kidneys by causing a buildup of acid, and may also cause kidney stones.

Most studies of high-protein diets have not lasted longer than one year, so the long-term effects of consuming this type of diet are not well understood.

How much protein do you really need?

The amount of protein that’s right for you is determined by how many calories you need, which in turn will be influenced by your level of activity. Online calculators are available to help determine how many calories you need depending on your goals and activity level. Then you can figure out many calories should come from protein. According to the 2010 Dietary Guidelines for Americans, it should be between 10 and 35 percent of your total daily calories. If you are consuming a 2,000 calorie-a-day diet, that’s between 200 and 700 calories of protein a day.

What does that look like? The palm of your hand (without fingers) or a deck of cards represents about 3 ounces. Three ounces of chicken has about 100 calories and 18 grams of protein. A 3-ounce hamburger (97-percent lean) has 164 calories and about 22 grams of protein. An egg has 72 calories and a little more than 6 grams of protein.

If you’re eating protein at every meal, you’re probably within the caloric range and consuming the recommended amount of protein. The Dietary Reference Intake (DRI) is 56 grams of protein a day for men over the age of 18 and 46 grams per day for women over 18. Consult with your doctor before starting a new diet.

In reality, most of us are probably eating more than the recommended amount of protein. If you have a glass of milk or cheese on that burger, you’ve likely gone over. But those guidelines are for people who are getting less than the recommended 30 minutes a day of moderate physical activity. If you are very active, work out regularly, or are pregnant or lactating, you need more protein.

To figure out specifically how much protein you need, divide your weight by 2.2 to determine your weight in kilograms. Multiply that number 0.8 if you are sedentary, or a higher number — up to 1.6 — if you are fit and active to determine how many grams of protein per day you should eat. Research indicates that any more than double the DRI won’t have a beneficial effect.

Strive to maintain nutritional balance

It’s important to make good protein choices. If animal protein is your main source, choose fish, chicken, lean pork, and limited lean red meat. Eggs and low-fat dairy products are also good sources. And don’t forget about plant-based sources — tofu and other soy products, nuts and nut butters, seeds, quinoa, and legumes such as kidney beans, pinto beans, garbanzo beans, split peas, and lentils are good choices.

Eating a high-protein diet for a limited time probably won’t hurt, may result in rapid weight loss, and could have a number of other benefits. But it’s important to ensure you’re getting the other nutrients you need to maintain your health. Research shows that all diets are effective as long as you are creating an energy deficit by reducing calories, increasing activity, or both. The best diet for you is the one that you will stick to.