There are several reasons why you may need more protein in your diet: 

1. if you are over 50 years of age
2. if you are physically active or just beginning an exercise program
3. if you are on a weight loss diet or are a weight loss patient

As aging and physical activity cause muscle breakdown, protein helps maintain muscle mass, and the body uses protein to rebuild muscle. 

Protein supports metabolism.  You need protein and calories to maintain your muscle. 

Weight loss surgery patients have a absorption change in the body, which means frequent small meals with protein will be needed to meet your nutritonal needs. 

You can calculate how much protein you need by multiplying your body weight by 0.5 (moderate) or 1.0 (high) to get the number of grams per day.   Then you can divide the total number of grams needed into 5-6 meals a day.   You can see why you need protein powders, shakes and supplements to help you get your daily requirements. 

Below is a chart printed in Obesity Help Magazine written by Dr. Christine Gerbstadt, who is not only a physician but a registered dietitian. 

• 3 oz lean meat (beef, pork, chicken, turkey, lamb)    15-18 grams of protein
• 3 oz fish (salmon, tuna, mackerel, sardines, or other fish, shrimp, crab, lobster)  18-21 grams of protein
• 2 medium or 3 whites (egg, egg substitute or egg whites)  11 grams of protein  
• 1 cup legumes (pinto, black beans, garbanzos, kidney, red beans, and others)  12-15 grams of protein
• Soy (tofu - 1 cup, soy milk - 12 oz, soy nuts - 1/2 cup, cooked soybeans 1/2 cup, soy protein powder - 1 oz)  11-16 grams of protein
• 1 oz  Whey protein powder   23 grams of protein