How It Works
The digestive system is the set of organs that break down and extract nutrient from the food we put in our body. It is a long tube that starts at the mouth, travels through the stomach, the large and small intestine, and end at the anus. Humans are kind of like a sophisticated doughnut... a sophisticated doughnut that if fueled properly can be pushed physically to resemble Greek Gods and Goddesses. Some fad diets of today favor a process in which you push your body into a state of Ketosis. Ketosis is a normal metabolic process, something your body does to keep working. When it doesn't have enough carbohydrates from food for your cells to burn for energy, it burns fat instead. As part of this process, it makes Ketones. In diets like this, you are essentially starving yourself to see results, when real Bodybuilders and physique competitor knows it take a perfectly balanced diet over several years to see the results of a Mr. or Mrs. Olympia. Gender is not a problem when it comes to diet, the human body is essentially identical once you remove visual, and sexual characteristics. It's simply a matter of intake that must be tailored to each individual person according to size, physical expenditure, and goals of the person. Protein has been consumed since ancient times, and one could argue that the digestive process starts as soon as you cut the meat on your plate, or start blending your protein powder.
With current technology, the time in which protein powder is broken down in the digestive system is far more rapid than what was being produced in the 1960's, 70's, and even the 80's. Modern nutritionist might prompt athletes to drink a protein shake right after their workout in what they call a "Metabolic window" but even then there are various restrictions and guidelines that you would have to follow to order to even hit these milestones. basically, there is a 30 minute window after a workout in which your diet can help turn cells from an Anabolic state, to a Catabolic state. in a catabolic state, cell break down large molecules into small molecules. whereas in an Anabolic state its just the opposite, in that small molecules are converted to large molecules. This is important because after a workout you want your muscles to grow right? This process is done in the catabolic state when your cell convert nutrition into muscle building "Leggo's."
If you ever hear a story or ad about the speed in which a protein powder is digested, just know that to the average person this doesn't matter. The food you consume will be broken down and digested no matter what. This process is tailored to people in the Cross Fit games for example, athletes who practicing intermittent fasting, or perhaps people on a weight loss journey.
The protein powder in the 1950s would have been slow digesting yet at the same time be very filling. The protein powder of the 50s was course, grainy, and did not have a very delightful taste. As technology progressed companies would be abel to produce and finer, higher quality protein shake. the 1960s saw and increase in the pre made ready to drink shakes, that were very filling, yet packed with preservatives and other fillers to act as a meal replacement. the 60's, 70's, and 80's were all constrained by the manufacturing process. The protein powder produced during this time would be nutritionally deficient compared to modern availability. Although effective as a meal replacement the protein powder was not as tasteful as consumers desired. throughout these decades a rise in the fitness industry would mean a rise in the demand for a high quality protein shake.