The issue with over restricting calorie intake with the goal to lose fat.  ( Please note, a calorie deficit is necessary for fat loss, however we do not recommend being in a deficit forever.)

Many people who decide they want to lose weight, immediately turn to calorie counting and reducing the energy intake, this normally works for quick weight loss goals, however, becomes a major issue when attempting to keep it off! When fat loss is the goal you should focus on speeding up the metabolism rather than decreasing your calorie intake which can lead to a slower metabolism.

Adaptive thermogenesis is the process of your body adapting to lower calories and as a result, burns fewer calories, at the opposite side your body will burn more calories when there is more to do so. It's just the process of fueling your body for everyday life, especially if your exercising. The real issue with adaptive thermogenesis is that if you consistently eating at a calorie deficit then your body will adapt to that, so as time progresses you will need to cut calories again to lose weight, basically meaning you are always eating less and less, which can't be maintained.

PS: We do talk about the importance of a calorie deficit as it is the best way to lose weight, however, we don't recommend you maintain as a lifestyle, it should be used for a short period of time to accelerate fat loss. Just noting this again.

Coach Zac​