Weight gain is impossible without the necessary amount of calories. It is the simple law of conservation of mass/energy.
160 calories * 21 days = 3360 calories. This is enough to gain about 1 pound of weight, not 19.
160 calories * 21 days = 3360 calories. This is enough to gain about 1 pound of weight, not 19.
However, you're really oversimplifying weight gain. Hormones play an important role in how much fat is stored and how much your metabolism burns. And the type of food you eat can affect your hormones.
>Hormones play an important role in how much fat is stored and how much your metabolism burns. And the type of food you eat can affect your hormones.
It doesn't matter if 100% of the calories he ate was turned into fat.
>how much your metabolism burns.
Eating sugar causes your metabolism to slow down by 4x? You'd die.