The Caloric Balance
What is a caloric balance? The caloric balance is balancing your eating and your physical expending of the energy you intake from consuming food.
IN - OUT = BALANCE
Your IN
Humans gain energy from eating food, and that energy is often measure by the unit calories. You may recognize this unit on nutrition labels. For example, a
medium size apple contains 72 calories, a glass (250 mL) of 2% fat milk, 128, an egg (50 g), 78, and McDonald’s Big Mac, 5632.
The sum of all the food you eat in a day (your intake for that day) is called the daily caloric intake (DCI). That is, the more food you eat in a day, the higher your daily caloric intake is, and vice versa. The average daily intake, in the US, was 2,618 calories for men and 1,877 calories for women in the year 1999-2000.
Your OUT
The human body uses the energy gained from consuming food in two main ways: to
fuel the metabolism when resting and for physical activities.
Resting metabolic rate
The resting metabolic rate refers to the energy your body spends when you’re not doing anything that requires any physical effort, such as sitting or sleeping. It just uses enough energy to keep your body’s vital functions alive. That includes
tissue regeneration, regulation of the body’s temperature, breathing, blood
circulation and filtering, and hormonal and nervous activity. These functions
are carried out by your liver, brain, heart, kidneys and muscles; these organs
and tissues work all the time, even when you’re not. Thus, when you’re not doing anything , your body still is, and that takes energy. Actually, since you rest for about a third of the day, you spend more energy on resting than anything else.
Physical activity
You have to spend energy to do anything. Other things, that involve motion and work, use, of course, more energy. Whether it’s moving from your bed to the
shower in the morning, from home to work or school, and so on. Even when
you’re sitting or standing, your muscles spend energy so you can maintain
good posture. The amount of energy you spend that way in a day on what you do. Someone who does a lot of physical activity obviously uses more than someone who sits around all day. For example, people who bike to work use more than those who drive.
Sport and physical exercise also increase the
amount of energy spent on physical activity. For example, a 121 pound
individual would spend roughly 75 calories per hour when sitting, 200 when
shopping and about 450 when walking at a fast pace. Ultimately, physical
activity can account for between 20 (little or no physical activity) and 50 %
(athletic activity) of your daily caloric expense. In conclusion, the more physically active you are, the more physical activity increases your daily caloric output.
Interestingly, exercise affects your OUT in two ways: first, it raises your daily output the days you are exercising. Second, in the long run and as you slowly build muscle, it increases your resting metabolic rate. The fact is that a pound of muscle is a lot more “active”, from a metabolic perspective, than a pound of fat.
Muscle contracts when you move, is put under stress when you train and constantly rebuilds itself to sustain its daily effort. As we have seen, energy expenditure can also be calculated in calories. Your daily caloric expense (DCE) is the sum of the energy required by your metabolism at rest in a day, plus the energy used to do physical activity in that same day.