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Martina M. Cartwright
Martina M. Cartwright Ph.D., R.D.

Three Reasons Dieters Should Eat More Protein

How dietary protein helps people shed weight

Why do people lose more weight eating high protein diets? Dietary protein is unique among the macronutrients in its ability to reduce fat and body weight. Unlike the other two macronutrients, fat and carbohydrate, protein preserves energy-burning muscle tissue and boosts energy expenditure because of three key characteristics exclusive to protein.

1. Dietary protein squelches hunger. Protein is the most satisfying of all the macronutrients. High protein meals suppress appetite by creating a feeling of fullness. This is one reason why an 80-calorie egg is more filling than a calorically similar glass of carbohydrate rich orange juice. Feeling full reduces calorie consumption thereby promoting weight loss. However, this effect is dependent on the type and quality of protein. Higher quality proteins, found in meat, fish, eggs, dairy (whey) and soy quell hunger more so than veggie proteins like legumes and seeds.

2. Protein digestion and metabolism burns more calories. Simply eating protein increases caloric expenditure. Higher-protein diets help shed pounds because protein digestion and metabolism are energetically expensive processes. Both dietary carbohydrate and protein provide the same amount of available energy, 4 kilocalories per gram, but it takes about 25% more of that energy to process protein. This means both energy expenditure and the thermic effect of food, or the energy cost to metabolize a protein meal, rise and thus more calories burned.

3. Protein increases lean body mass or muscle. Muscle burns calories. When people shed weight, muscle mass is usually lost. But studies show that overweight dieters are more likely to lose fat instead of muscle by following a higher protein, lower calorie diet. The muscle-building effect of a higher protein diet is further boosted with resistance exercise.

Protein recommendations vary based on activity level and health status. For adults, an absolute amount of protein, 0.8 grams – 1.2 grams per kilogram body weight, is necessary to promote satiety and weight loss. Higher amounts boost muscle mass. Healthy yet sedentary adults need about 0.8 grams of dietary protein per kilogram body weight. For endurance athletes, 1.2-1.7 gm/kg is suggested and 1.4-1.8 gm/kg for strength athletes. There is no benefit in consuming over 2.0 gm/kg. A higher protein diet for weight loss is considered to be about 1.0-1.2 grams/kilogram body weight or up to 30% of total calories coming from protein. A registered dietitian can design a tailored protein diet that meets your specific needs. (

Adding protein to your diet is easy especially since the market is flooded with new higher protein products like cereals and Greek yogurt. Including at least 15 grams of protein in each meal suppresses appetite and preserves body protein. Starting the day with a protein rich meal is especially important. Consuming protein for breakfast reduces calorie intake for the remainder of the day. This is one of the reasons why cereal companies have launched high-protein cereals packed with pea protein, nuts and seeds. According to Mangala D’Sa the brand director of Post Grape-Nuts and Great Grains, “A short-term study in April’s American Journal of Clinical Nutrition found that a breakfast with a higher protein content turns down areas of the brain responsible for food cravings. So starting the day with a cereal like Grape-Nuts Fit can help consumers stay satisfied.”

Protein is an essential macronutrient that can facilitate fat loss and muscle maintenance if consumed in moderation. Including dietary protein in every meal can boost metabolism and preserve valuable muscle. Higher protein diets aren't for everyone. If you have a health condition, kidney function problems or chronic disease, check with a registered dietitian or physician before starting a higher protein diet.

About the Author
Martina M. Cartwright

Martina M. Cartwright, Ph.D., R.D., is an adjunct professor of Nutritional Sciences at the University of Arizona and an independent biomedical consultant.

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