Your friend has an interesting perspective on the word diet. I was wondering how far one can take his/her interpretation of the word. Would it make sense to say that (die)iticians have chosen the wrong profession because the word “die” can be found in its prefix? Too, does the word diet only refer to what comes to the minds of many when they hear the word? Calorie restriction, avoidance of certain foods that contribute to weight gain or whatever negative connotation people associate the word diet with.
In the medical field depending upon one’s health status specific diets are prescribed for reasons other than weight loss. For instance:
1. Residue free diets – This way of eating is great for people who live with Crohn’s disease
2. Purine restricted diets: This diet is ideal for people who have gout.
3. High residue diet: Great for folks who get constipation
4. Gluten free diet: Used in the management of celiac disease
So to answer your question, I believe in the word diet. My definition is just a bit broader.
Thanks for the question.