Saying that it categorically works is pretty misleading. Many people try straightforward calorie reduction and find that besides experiencing extreme discomfort

Saying that it categorically works is pretty misleading. Many people try straightforward calorie reduction and find that besides experiencing extreme discomfort from cravings and reduced metabolism, they make very little progress over periods as long as a month and these people often walk away thinking that weight loss is impossible for them. The truth is that many people are metabolically imbalanced or diseased and will not respond the way a young otherwise healthy man does to caloric restriction. Calories in, calories out is certainly true because we know the laws of thermodynamics are obeyed by the human body. However, there are all sorts of subtleties here. For instance, one person might not absorb all the food they're eating and may shit out much more viable calories than another person. Further, we know that hormones play a dramatic role. Look at pubescent boys versus pubescent girls. In both cases, caloric intake goes up (it also doesn't go up consciously, the kids are signalled to eat more by their bodies and are nearly helpless to do otherwise) but what is done with the excess calories is different in boys versus girls due to hormonal influence. In boys, the majority of excess calories goes into creating more lean tissue whereas in girls it is much more balanced between lean tissue and fat growth and the fat distribution is not the same as boys. Hormones are an important factor in weightloss and weight gain and should be considered. This is just my long-winded way of saying: yes, simple caloric restriction works for many people, but among many people with hormonal and metabolic problems, caloric restriction is much more likely to result in needless suffering and poor results. If the conversation focuses solely on simple caloric restriction, then these people who likely make up the majority of obese people will likely never get the information they need to find strategies that work for them.