Soldato
I'm talking specifically about the kind of people whose diet consists of only a dozen or so foods as everything else is deemed unclean or because they like to prep a weeks food at a time and eat the same thing every day - a non-varied diet like this can lead to deficiences, which studies back up (pulled from the Eric Helms metastudy)
Kleiner SM, et al. Metabolic profiles, diet, and health practices of championship male and female bodybuilders. J Am Diet Assoc. 1990 Jul;90(7):962-7.
Kleiner SM, et al. Nutritional status of nationally ranked elite bodybuilders. Int J Sport Nutr. 1994 Mar;4(1):54-69.
Keith RE, et al. Nutritional status and lipid profiles of trained steroid-using bodybuilders. Int J Sport Nutr. 1996 Sep;6(3):247-54.Hoffman JR, Falvo MJ.
That is true if you're working on the assumption that IIFYM is an actual diet - which it isn't - and the majority of people using it only care about hitting numbers, not food quality, which they don't.
I think the problem is places like Instagram give off this impression, but in truth most people only take pictures of their bizarre protein cereal sludge creations and tend not to post the other 80% of their intake since chicken salads or bowls of oats aren't deemed exciting enough. As said, even if you're fairly liberal about food quality in hitting your numbers, the actual composition of most of that kind of food makes it extremely difficult for it to make up a large % of your macros.
The primary difference I've seen between Flexible Dieters and more traditional types is more an attitude thing - the latter will do, quote unquote, cheat days or meals, where as the former just incorporate a similar volume of that food into individual meals or days without the labels or connotations certain foods are good or bad (in isolation, at least).
