Science behind the rich protein only diet for weight loss

To understand this concept we need to understand the role of insulin and glucagon in our body. Both are secreted by pancreas. Both work in opposite direction. The insulin reduces the sugar level in the blood if it increases to a threshold. The glucagon increases the blood sugar level if it reduces to a threshold.
There are three phases in the digestion process. 1) cephalic phase 2) absorptive phase 3) fasting phase. The cephalic phase starts from the sight of food or from the thinking of food and completed before the absorption take place. The absorptive phase starts after the digestion carried out and the energies are about to absorb in the body. This phase will end either by placing the energy in the blood or by storing the energy in body. The fasting phase starts when the stored energy such as fat, glycogen and protein are about to convert back to usable energy.
The insulin secreted in the cephalic phase and adaptive phase. The glucagon secreted in the fasting phase.
When we consume only protein, we are missing carbohydrate in the diet and consequently the sugar level in the blood sugar reduces and reaches to lower threshold. The glucagon is secreted and converts the stored energy to sugar to increase the blood sugar level. If we continue on rich protein only diet, the glucagon’s activity will be high and we loss the weight slowly.