If you need to reduce calories, start by reducing your fat intake. Keep your carbohydrate and protein consumption as high as possible for as long as possible to maintain your energy. Just don't let your total fat intake dip below 10 percent of your total daily calories. Having fewer fats than that in your diet can harm your performance, recovery, muscle maintenance, and testosterone production.
The prevailing formula for a long time on how much fat you’re going to burn was calories in minus calories out, based on your basal metabolic rate (BMR) and exercise efforts, explains strength and performance specialist Joel Seedman, Ph.D., owner of Advanced Human Performance in Atlanta. But with all the different biochemical reactions in the body, hormonal response, and endocrine function, there are an infinite number of factors that can affect how your body is storing and breaking down calories.