Finding the key to weight loss success

Nutrition is concerned with overall health, not just weight. Nutrition cares if someone has high blood pressure or diabetes, or if the mass is a small chunk of lean muscle or huge blobs of adipose tissue. Weight has absolutely no idea about such things. The numbers on the bathroom scale give very little information about overall health.

However, as long as we're talking about ONLY numbers on the scale rather than overall health, "calories in versus calories out" is fundamentally true. It's basic physics. Still, "calories in versus calories out" is so general that it's utterly meaningless. It carries no more information than saying "Life comes down to living". The devil's in the details. For example, certain "calories in" interact with emotions and satiety receptors, so some foods may reduce the total amount of "calories in". Also, some foods might help digestion, or they may be more easily eliminated, so the type of "calories in" may affect the amount of "calories out". Furthermore, certain calories in might more easily turn into muscle instead of fat, so those types of food may change the level of future "calories out". The timing of the "calories in" may change how many calories go out by changing the person's metabolism.

All the details about what types of things people eat, how they exercise, when they do it, etc., can change how many calories go in and how many come out. It can change how easy or difficult it is for those calories to go in or out. But, nothing changes the fundamental laws of physics that calories don't just disappear. If the calories consumed don't come out one way or another, they will add to the person's weight. That weight might be lean muscle or cellulite. That weight might be making people healthier or less healthy. That weight might make it easier to gain or lose weight in the future. But, the calories that go in and don't come out is still going to be weight.

Finally, the body likes being efficient. The reason that people plateau is that the human body is very highly adaptable. It's going to try to adjust to anything that becomes routine. So, if you eat and exercise the same way every day for a year, a routine that burns 100 calories today isn't going to still be burning 100 calories a year from now. The "calories out" side will change. The body will change its composition and its chemicals to adapt to the routine, so the number of calories out is going to be different. The body tries to optimize and become more efficient. It's a very useful survival mechanism. A long-term calorie deficit is likely to signal a famine, so it's useful for the body to adjust itself to burn fewer and fewer calories (or come up with some other survival mechanism -- not all bodies are going to react the same way) so that the organism can outlive the famine. Our bodies' built-in survival mechanisms will change the "calorie out" side to work against long-term weight loss.

There are many variables, and health is very complex. I find it disturbing that doctors insist on educating patients using such simplistic shortcuts when they know it's not that simple. Yes, "It all comes down to calories in versus calories out," but that just doesn't say anything useful or answer the patient's question.