*mooncup...people get fat when they eat too much because if we put more calories in than are going out our bodies turn those extra to fat.
that is undisputed scientific fact*
This is actually very much disputed. It is not clear that the laws of thermodynamics (i.e. calories in calories out) is correct.
Someone eating 5000 calories of pizza and someone eating 5000 calories of steak - balancing out their state of calorie useage - would they put on the same amount of weight?
The answer is very very much disputed.
The body does not seem to comply with simple thermodynamics (CICO) because it metabolises different food groups differently (carbs turn into glucose, protein into amino acids and fat into fatty acids)
A calorie does not seem to be a calorie.
To quote what insulin does (produced by the pancreas in response to eating carbs/sugar):
"Insulin is the hormone that tells our cells to pick up glucose from the bloodstream. It is also the major energy storage hormone in the body. It tells our cells to store energy, either as glycogen or fat"
Insulin plays a big part in laying down fat stores in the cells. Insulin literally regulates the body and decides whether or not the extra glucose from food gets stored as fat.
So anyway, it is disputed because people who are eating diets that are constantly spiking their insulin may not be using the stored fat they have for energy and this means at a day to day level, they will be constantly hungry - and the availability of snacking makes this possible. This is also why fasting is such an important thing - if you fast you starve your body of instant glucose, and so it has to start using the stored fat as energy. Most people these days are eating every few hours - we usually have 2-3 hours of stored glycogen, so are never going into 'fat burning' mode.
Anyway, the calories in calories out hypothesis is very much disputed!