To build muscle you need to ingest more calories than you need, on the other hand you have to ingest fewer calories for losing body fat. This is diametrically opposed to each other. What do you then do to both goals? That is alternating your calorie intake as detailed below. Just make sure that the ratio of calories from carbohydrates, proteins and fats about matches up with your daily energy consumption.

Heavier through fat burning and muscle building
Eat four to five days a week – about four pounds calories per kg body weight more than you need. Spread this over five meals per day.

example:

person of 75 kg
Eat 75 × 4 = 300 kcal per day more, this is
300/5 = 60 kcal more per meal.

Eat the other two to three days about four pounds calories per kg of body weight less than you need. Across five meals a day.

example:

eat 300 kcal per day less, this is equivalent
with 60 kcal less per meal.

Lighter by fat burning and muscle building
The opposite of what above. Eat four to five days a week – about four kcal per kg body weight less than you need. Spread this over five meals per day.

Eat the other two to three days about four kcal per kg body weight more than you need. Across five meals a day.

Weight maintenance but still burn fat and build muscle tissue
Half and Half.
Eat three to four days a week – about four kcal per kg body weight less than you need. Spread this over five meals per day.

Eat three to four days a week – about four kcal per kg body weight more than you need. Spread this over five meals per day.

Use the days that you train to eat more, and the days when you little to nothing does the days to eat less.