Calories play probably the biggest role in weight loss. Every food contains calories, If you are taking in more calories than you are using up in a day you will gain weight, if you are using up more than you are taking in you will lose weight, this is called a calorie deficit, and this is what you want to create.
The simplest way to go into calorie deficit is to eat less, the less food, the less calories you are taking in. Combine that with intense exercise and you are bound to create a calorie deficit and lose weight.
When you go into calorific deficit (using more calories than you take it) your body isn’t getting the amount of energy it needs from food, so your body begins to use its fat stores for energy, which causes a loss of fat from out bodies, which is usually what we want to happen! If you are constantly in calorie deficit you will continue to lose weight, and this can be dangerous.
The patches are great! They're so small and easy, and they do the job.

