I think the answer is that it's really hard to study this, since food diets are hard to control over long periods of times but that current research is consiste

I think the answer is that it's really hard to study this, since food diets are hard to control over long periods of times but that current research is consistent with calorie counts being a good estimator of a person weight gain/loss. Here's a reasonable summary with some studies you can look at for the details. [1] But this is certainly an area of ongoing research and the devil is in the details: does it matter when you eat? [2] Does your gut microbiome affect it significantly? Genetics? Is there inter-person variation in how their body adapts to different food? Does fat/carbohydrates/protein/fiber content affect satiety in a manner that helps people lose weight in real life situations even if it doesn't matter in a clinically controlled setting where overeating is impossible? We might never have full pictures of all these questions. [1] http://examine.com/faq/what-should-i-eat-for-weight-loss/ http://examine.com/faq/what-should-i-eat-for-weight-loss/ [2] I know specifically that this is currently being tested in some large-scale, high-cost studies. Which tells me that researchers aren't as confident as [1] makes it sound like.