Having been on 6 RS tours now, I wouldn't be concerned about the level of conspicuous consumption described by the OP.
How would I know the reason for It? Diabetic? Or maybe like my friend who had to eat so frequently that the 2nd thing she and her husband did after getting their rental car when they arrived by plane was to get a cheap styrofoam cooler and stock it with food for her. That was because when she needed to eat, she needed to eat immediately. Her metabolism was so high that she burned up anything she ate very rapidly.
As an example, I spent a day with her when she had a late lunch of a huge salad with lots of chicken and bread that would last most people at least 6 hours. We met our husbands about 3 hours later and she had a large pasta meal. She was slender, but not skinny.
Based on my RS tours, if she was on one she'd have to supply herself some way like the guy described because there simply wouldn't be enough breaks or decent meal stops for her.
As a person who doesn't consume alcohol, I'm a bit more put off by what seems to me to be a very high level of alcohol consumption on RS tours. I've often been the only person who didn't drink and in some situations there has been nothing else served that I could drink.
I'm talking about at wine or other kinds of alcohol production facilities, not group meals. I know it's cultural and people are on vacation, but booze at lunch and dinner whether with the whole group or not? Really?
I'd never say anything to anyone about that because it's none of my business and has no reflection on me. Most have held their liquor well, and I must admit that their behavior has sometimes been rather amusing.
Likewise, I wouldn't say anything to or about the breakfast buffet hunter-gatherer. Not my circus, not my monkeys.