Our body consumes the calories we consume into three areas: Carbohydrates, Proteins, and Fats. Our body needs all three. Carbohydrates are basically the fuel that runs the body. Proteins build muscles, repair bones, and repair injuries. Fat insulates and protects vital organs and is called upon for long-term energy. These are called macronutrients. Besides, the food also includes micronutrients, which include Vitamins and Minerals.
As we age, we lose muscle mass. As we lose muscle mass, our metabolism slows. As our metabolism slows, we gain weight.
In middle-age years we need fewer calories to maintain our weight, so we should eat less. Fat tissues do not use as much energy as muscle tissues, so we use fewer calories.
When we eat is just as important as what we eat. Rather than skipping and then feasting, eating smaller meals helps faster metabolism and weight control.