Insulin is needed to allow the cells in a body to absorb sugars as glucose.
That also includes fat cells.When your other cells don't need the sugars for fuel, it has to put the excess sugars some place.
Your blood levels have to be maintained.
•If you give your body a bit more energy than it burns every day, a portion of the excess energy is stored as body fat, and thus you gain weight slowly
•If you give your body a bit less energy than it burns every day, it will tap into fat stores to get the additional energy it needs, and thus you lose weight slowly
It takes time to make insulin If you are taking in more sugars,carbs than your body can manufacture then you need to supplement your insulin.
This condition is called diabetes. In order for your body to make insulin it needs 51 amino acids to make one insulin hormone.
This is where nutrition comes in to play, you have to have enough (nutrition) amino acids to make the the amino chains.
Insulin is a hormone. Your thyroid also secrets hormones which use amino acids (nutrition). If you live on empty calories (No nutrition) you would think that your thyroid would slow down or not produce and so it does.