This is going to be a short one, but since a lot of people are talking about dieting right now, it seemed a good time to discuss the topic. But first, a little biology lesson. As everyone knows, the heart pumps blood throughout the body. What most people are unaware of, however, is that the heart is not the only force at work. The walls of the arteries (the vessels that move blood away from the heart towards the extremities) are lined with smooth muscle that also assists in moving blood. Also, every contraction of our skeletal muscles (the muscles that move the limbs, expand the rib cage, and control posture) also serves to help assist the movement of blood throughout the body, and especially, helps blood return to the heart.
When a person spends most of their day in the seated position, however, most of the work of moving the blood is left to the heart. This means that the heart is using a lot of energy just in maintaining proper blood flow. Now, just for a moment, think of your feet. Imagine that the body is a mountain and the feet are the base of that mountain. Now picture the blood cells as mountain climbers. When a person is walking, that mountain climber has a full load out of gear and supplies as well as several assistants to help ease the trip. When that same individual is seated however, the climber in this example is tackling the mountain alone and under-prepared.
So what does this have to do with dieting? Well, when someone diets, he or she is usually changing the percentage and amount of carbs, proteins, and fats that he or she consumes. If that amount is less than the body burns during the day, weight is lost (in theory). However, the human body doesn’t always consult the brain’s intentions when these sort of things are done. The body, being wired to keep a person alive, usually interprets this removal of calories as the onset of a food shortage. As such, it will start being stingier with the calories it burns and will consult the lifestyle of the individual in order to figure out what it can burn and what it should hoard. If a person is still physically active, the body will burn the types of calories as needed to maintain that level of activity. If a person is sedentary, however, something very interesting can occur.
So, as mentioned in the previous paragraph, the body will consume calories based on what’s needed. Well, one of these needs is moving blood throughout the body, which for a sedentary person, means a lot of work for the heart. Since the rest of the body isn’t assisting in moving blood, the heart ends up being solely responsible. And here’s where diet comes in – the heart’s favorite fuel is fat. If the body has determined that the heart needs all of the fat it can find to keep working, it will start hoarding that fat. If the individual’s diet has recently changed so that the amount of fat it contains has decreased, this is a further incentive for the body to hold onto what fat stores it has. It will even get to the point where the body will start shrinking the muscles while still holding the fat stores in order to maintain this “strategic fuel reserve”.
As can be imagined, this behavior by the body is pretty much directly contradicting the goal’s of the individual dieting. So what can be done? First off, don’t diet. The best way to lose weight and gain muscle is to increase the demands placed on the body without changing the amount of food going in. If a person starts to feel overly tired, look at the types of food. Avoiding processed foods can take a tremendous load off the cardiovascular system and speed the process along by reducing the workload on the heart. And, contrary to the dieting advice of the 80’s, don’t be afraid to have a little fat in your diet. If the body knows more is coming, it won’t be so stingy with what it has.
Finally, the heart also needs oxygen to function properly, so if a workout is composed mostly of huffing and puffing, that means that the heart is having to rely more on burned fat as a fuel source. If that is the case, it will be less willing to part with it’s fat stores when they aren’t wanted by the individual. A simple way to maintain an aerobic state is check to see if normal conversation can be maintained. If so, then the muscles are getting plenty of air. If, however, there’s lots of gasping and gulping for air, ease off until breathing normalizes and then hold at that intensity. It may lead to less sweat but weight loss efforts will be more effective.