So many diets start by telling you the key is portion control and counting calories. They’re wrong. As I say on the Equations page, the prevailing idea that your body can somehow count the calories you eat, then gain or lose weight depending on whether you’re eating too many or too few just doesn’t make sense. There is no mechanism in the bodies of humans or other animals to do that. The kind of calories makes all the difference in how they are processed by your body. Sugars, fats, and proteins are metabolized very differently. Even within each group, the different sugars, amino acids (protein building blocks), and fats are handled differently. The most notable difference within sugars is glucose versus fructose. One, glucose, is not bad, especially if tied up in starches and fiber. The other, fructose, isn’t something our bodies saw much in nature and is handled very poorly, making you sick.
Yes, you can often lose weight by restricting calories. But that mimics starvation. An animal’s brain and body undergo a number of changes when it’s starving, mostly bad ones. Restricting calories while eating a low fat diet will usually generate stress, resulting in conditions like elevated cortisol, the stress hormone. Depending on your own individual genetics and what exactly you’re eating, your brain and body may want to partially shut down to save energy. You may lose muscle mass as well as fat. In other cases, it may cause elevated activity and anxiety as the starving animal inside you wants to find food. If you’re eating a diet that’s badly enough loaded with toxic sugars, you could end up malnourished but still trying to deposit fat because that’s all your body can do with the sugar.
Calorie restricted diets are famous for yo-yo effects. You lose some weight, then go back to eating the wrong high carb/sugar food, then gain the weight right back. Do you want that life? Worse, would you really want to spend the rest of your life in a semi-starved condition? Why not learn to eat foods that your body handles properly so that it naturally shifts to a body composition that’s normal for the human animal?