A lot of your comments are not quite correct.
1. glucose in food can be absorbed directly through the mucous membranes in your mouth. In less than one minute. Diabetics who experience low blood sugar from medicines like insulin may suck on high-glucose candy, which quickly enters the bloodstream as glucose. Solves the problem in a very few minutes.
2. starch takes longer to convert to glucose, but not 10 hours, more like 30 minutes to one hour. Excess glucose from a high starch meal is converted to glycogen in the liver and muscle tissue. Glycogen is an intermediate energy source that you can access during exercise.
3. Exercise stimulates peristalsis (muscle contractions that move food through the gut). Is that what you are referring to in terms of speeding up digestion? It is common for distance runners to experience sudden bathroom urges. I know one who knows first hand every bathroom on all of his training routes.
As humans age their daily caloric requirements decrease, meaning they need to eat fewer calories. Unfortunately, many older people have a diet that is marginal in protein. As they reduce calorie intake, protein intake can become sub-optimal (Not good). If an older person exercises or works hard that person needs more calories, and the protein problem may not exist. Older "feeble" people have a problem called sarcopenia. Low protein intake, low levels of exercise are most of the causes of this problem. Increased exercise and sufficient high quality protein help to retard the onset of sarcopenia.
https://en.wikipedia.org/wiki/Sarcopenia
Dietary protein requirements are also a function of muscle mass. Normal males have more muscle per Kg of body weight than normal females of the same weight. In this case males need more protein per day.
Conversely, a female Olympian that weighs 60Kg requires a lot more calories and protein than does a male couch potato of the same weight. So exercise does strongly impact dietary requirements. (couch potato == someone who sits for most of the day, with minimal exercise)
A lot of the WHO dietary information is for hypothetical people, since they try to accommodate everyone's needs and available food resources to some extent.
WHO CINDI:
www.euro.who.int/__data/assets/pdf_file/0010/119926/E70041.pdf
US:
https://www.cnpp.usda.gov/2015-2020-dietary-guidelines-americans
Does this help to answer your question?
