Many people mistakenly think that if they eat lots of protein their muscles will get larger and that excess protein won't lead to increases in body weight. Well that's just not true! As nutritionists we've known for a long time that there is a limit on how much protein the body/the body's muscles will use and that protein contains the same number of calories as carbohydrates - 4 calories per gram. Thus, the daily recommendation for protein is 0.8 grams per kilogram of body weight or 10-35% of calories for the generally healthy person.

For example, if someone weighs 150 pounds and eats 2000 calories per day, he/she should consume:

150/2.2 = 68 kg

68 kg x 0.8 = 55 grams of protein

OR

2000 x .10 = 200 calories from protein/4 calories per gram = 50 grams of protein

2000 x .35 = 700 calories from protein/4 calories per gram = 175 grams of protein  

50-175 grams of protein per day

New research from the University of Texas Medical Branch at Galveston¹ takes this a step further by suggesting that the body can only use 30 grams of protein (a 4-ounce serving) per meal for muscle protein synthesis (production). Therefore, 4 ounces (approximately the size of a bar of soap, a checkbook, or a deck of cards) of chicken, fish, dairy, or lean beef may be all your body can use at one time.

Here's more detail from the study... researchers compared changes in muscle protein synthesis in response to a single moderate serving (30 grams protein or 4 ounces) or large serving (90 grams of protein or 12 ounces) of 90% lean beef in about 20 healthy young adults and 20 healthy elderly individuals. Study subjects were under resting/nonexercising conditions and provided blood samples and thigh muscle biopsies so that muscle protein synthesis rates after meal ingestion could be determined. In both young and old adults, researchers found that the large serving of beef gave exactly the same increase in muscle protein synthesis as that small serving.

Thus, while these results may not apply to highly active individuals, most Americans would probably benefit from spreading their protein consumption throughout the day - 20-30 grams at breakfast, lunch, and dinner - rather than 90 grams at dinner, given that excess protein consumed will be converted to glucose or fat and ultimately stored as body fat.

So what might a 20-30 gram of protein/meal meal plan look like? Here's an example:

Breakfast - 20 grams of protein

1 whole wheat english muffin with 2 tsp soft margarine; 1 medium grapefruit; 1 hard-cooked egg; 1 cup fat-free milk 

Lunch - 30 grams of protein

2 slices rye bread; 4 ounces tuna (packed in water) mixed with 2 tsp mayonnaise and a splash of lemon juice; 2 slices tomato; 1 medium pear

Dinner - 30 grams of protein

3 ounces roasted skinless chicken breast; 1 large baked sweet potato; 1 ounce whole wheat dinner roll with 1 ounce soft margarine; 1 cup leafy green salad with 3 tsp oil and vinegar dressing

Sure don't need big portions of steak or protein supplements to meet these recommendations, do you?!?

¹Symons, T.B. (2009). A Moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects.. Journal of the American Dietetic Association, 109, 1582-1586.