There were worm studies that indicated carbohydrate restriction worked much better than straight calorie restriction:

'Spoonful Of Sugar' Makes The Worms' Life Span Go Down

Which was good enough for the lead researcher to go low carb. Good enough for me! That, in fact, it was the carb restriction, inevitable with calorie restriction, that sparked the good results.

High carb foods don't tend to be the most nutritious items around, either. A piece of meat makes them look pathetic, and they are not only low on micronutrients, they can block the body's absorption of same.

High infection rates might come down to malnutrition.