More than 10,000 different proteins make a person what they are. Protein is found throughout the body--in muscle, bone, skin, hair, and virtually every other body part or tissue.
Complete vs. Incomplete Protein
There are 20 amino acids that are the building blocks for all protein. The body can make eleven of them (non essential) and the remaining nine need to be taken in, which come from the diet (essential).
Complete protein sources contain all the amino acids needed to build new proteins. Animal protein sources (meat, fish, poultry, milk, cheese, and eggs) are usually complete. Gelatin is the only incomplete animal protein. Soybeans are the only plant protein considered to be a complete protein. 
Proteins lacking one or more essential amino acids are called incomplete proteins. Beans, grains, nuts, fruits and vegetables tend to be incomplete proteins.
Incomplete proteins can be combined (by consuming different protein sources) to make complete protein. It was believed that these foods had to be eaten at the same time in order to be used by the body to build protein. Studies now show that the body can combine complementary proteins that are eaten within the same day.  Examples of combining incomplete proteins include: macaroni and cheese; yogurt with granola; peanut butter and toast.
A patient needs a daily supply of amino acids to make protein because the body doesn't store amino acids like it does fats or carbohydrates. If protein is not consumed in the diet, the body will use the only available source - muscle tissue - to get what it needs. Less muscle tissue further contributes to a slowed metabolism, and reduced fat-burning.
Recommended Dietary Allowance (RDA) for Protein
The Institute of Medicine recommends that adults get a minimum of 0.8 grams of protein for every kilogram of body weight per day, for an unstressed body, to keep the body from slowly breaking down its own tissues . That's about 8 grams of protein for every 20 pounds of body weight.
RDA of protein for women ages 19-70 is 46 grams per day. 
RDA of protein for men ages 19-70 is 56 grams per day. 
It has been estimated that Duodenal Switch patients' malabsorption is 40% of their protein intake. As a result, surgeons generally recommend a daily protein intake of 80-120 grams to their post-op patients. [41-43], 
The additional protein is also required any time the body is stressed above the baseline. This includes any illness, trauma, injury and post surgical state.
Protein Content in Food
For most post-operative patients, after DS, it may be nearly impossible to get the required protein in by the means of meals. If patients are not able to get their daily protein requirements through their diet they should use protein supplements. Supplemented protein is bio available and is absorbed extremely quickly. Look for protein supplements that are low in carbohydrates. There are numerous protein supplements available commercially and IT is best to rotate the types of protein used.
Myth or Fact: Can 30 grams of protein be absorbed at a time?
Does a person with an unaltered anatomy only absorb 30 grams of protein at a time? There is some scientific data to support this position. However it requires extrapolation of data. In a study  that when two groups of patients were given two different amounts of protein (30 grams and 90 grams), the amount for protein utilization as indirectly measured by muscle production (reflecting the ability to absorb protein and utilize it) did not increase or correlate with the amount of protein taken. The study concluded that it is probably more important to consume small volumes of protein more frequently versus a few meals with large protein content.
Bioavailability of Protein Types
Bioavailability refers to the protein's ability to be used by the body and it is measured by Biological Value (BV). The higher the BV, the more bioavailable the protein. The BV numbers below demonstrate how easily the body (pre-DS) can absorb these protein types. The last few protein types mentioned on the list would need to be blended to make a complete protein.
Whey blended products, BV 100-159
Whey, BV 104
Egg, BV 100
Cow's milk, BV 91
Egg white, BV 88
Beef, BV 80
Fish, BV 79
Chicken, BV 77
Casein, BV 77
Soy, BV 74
Potato, BV 71
Rice, BV 59
Wheat, BV 54
Beans, BV 49
Peanuts, BV 43
Post DS patients need to keep in mind that they do not absorb protein from food as well as an individual with a un-altered GI anatomy. Pre-digested (hydrolyzed) protein supplements (like whey) are more highly absorbed and help our bodies get the proper nutrients we need.
Make sure the protein powder or drink states that it is pre-digested or hydrolyzed, and the best kind of protein would be a whey blend protein. Second best would be a 100% whey protein. Isolates, though good for a quick acting pick-me-up, are not sufficient alone for post-op DS patients on-going maintenance requirements.
Protein Supplement Recommendations
Protein supplement preferences vary person to person. If possible try samples of the supplement before investing in a large container. Also, your tastes before and after surgery may differ, so wait until you are post-op before sampling.
When post-op Duodenal Switch patients were asked about their favorite protein shake here are the overwhelming reported top 3 and how the nominators make it.
Pure Whey Stack
- Put 1.5 scoops in 4-5 oz. water, shake well, and serve over ice.
- Simply mix it with a fork with cold water and add ice.
- In a blender mix 1 cup of milk or water, 1 heaping tsp of instant coffee, 2 scoops of protein powder, 4 ice cubes.
- Mix it with ice and water, or ice and soy milk in a magic bullet for a shake!
- Shake 6-8 oz. water
Pure Whey Stack
- Milk, whole banana, ice = Milk Shake.
- Put 1.5 scoops of protein in 6oz Lactaid Milk, blend well in Magic Bullet, and serve over ice.
- 2 scoops powder, 2 c. crushed ice, 1 c. half & half - all whizzed up to milkshake consistency in my blender.
- Mix slurry 1 1/2 scoops of protein powder in 4 oz. of cool water and 2 oz. of 1/2 & 1/2. Pour hot coffee into the slurry and stir.
- A "glop" of DaVinci sugar free caramel sauce + 8 oz. water + ice, blended.
- 1/2 cups half & half, 1/2 cup Oregon Chai Tea (I use slightly sweet but there is also sugar free), 1 scoop IDS Cinnamon Vanilla. Heat half & half with Oregon Chai until luke warm. Stir in powder, heat in 20 seconds intervals until hot.
For Vitalady's Protein Comparison Chart: