The Science Of Fat: The Importance of Base

By CEO Robert Forster, PT

There has been a lot written about fat in both the popular press and in sports related journals and magazines. We: athletes and the sedentary alike, are a society obsessed with fat; in our diets and on our bodies, and with good reason. Over 1 million people worldwide are overweight and in many countries including the U.S. these numbers are increasing at an alarming rate. Sixty five percent of U.S. adults are overweight compared with 56% a decade ago. Since 1980 obesity in children has escalated three-fold and now 15% of children over six are overweight. Some scientists think this generation may actually have a shorter lifespan than its immediate predecessor.Additionally, two effects of obesity; high blood pressure and heart disease have recently made the top ten list of global health risks from the World Health Organization.

As athletes we like to think we are granted protection from the detrimental effects of fat. We have been told that aerobic exercise produces high-density lipoproteins (the good cholesterol) that protect the heart and blood vessels against stroke and heart attacks. However, recent research indicates that just because you are fit doesn’t mean your body fat is not sabotaging your health. We can simply look back and recall the deaths of Jim Fix, the running guru and Ed Burke, the cycling physiologist who both died of cardiovascular disease doing what they loved; working out, to realize exercise is not the panacea protection against disease as once thought.

For sometime, sports scientists have understood that for athletes some fat is good. For the endurance athlete fat supplies are an abundant, clean burning energy source for workouts and performances. At the very least, conventional wisdom held, excess fat is nothing more than a very needy anchor slowing your pace and diverting a disproportionate and unproductive amount of oxygen rich blood flow from your working muscles. However, new research indicates fat is more evil than previously thought. More than an unsightly but inert substance hanging from your midsection and robbing your efficiency, fat is now understood to be a highly active metabolic tissue spewing damaging chemicals and hormones with profound and far reaching effects on health.

The fat cell, once thought to be a simple storage container for triglycerides is actually constantly secreting hormones and powerful chemicals much like the thyroid and pituitary gland. In fact, your collective fat cells, and there are many, up to 40 billion in a lean adult and 120 billion in the obese, act like one big endocrine gland. While the effects of proper thyroid and pituitary gland function is always positive for health, normal function of fat cells results in the secretion of substances linked to heart disease, high blood pressure, and some forms of cancer. Fat cells produce thrombotic agents that assist in clotting and chemicals that constrict blood vessels resulting in increased blood pressure. Together theses chemicals and their effects contribute to cardiovascular disease and stroke. Making matters worse, while adult endocrine glands do not grow, the fat “gland” grows readily.

Not only are fat cells quick to expand and slow to shrink, (indeed obese people have 50-75% more mass in their fat cells than lean people) fat has a nearly infinite capacity to multiply. Contrary to popular belief the number of fat cells is not fixed in childhood. As fat cells approach their limit in size, nearby dormant fat cells are signaled to multiply to handle the overload. Lastly, fat cells are extremely long lived as compared to other cells and once mature continue to poison the body for extended periods.

The first fat hormone discovered, Leptin, communicates with the brain to control metabolism and eating. The more bodily fat the more leptin produced to decrease appetite and maintain genetically determined levels of body fat. Unfortunately obesity creates a bodily resistance to the effects of leptin. The fatter we get the less appetite control exerted by this system. On the other hand, the hormone adipotectin produced by fat makes the body more sensitive to the effects of insulin. Insulin facilitates glucose (sugar) uptake by muscle cells and therefore prevents it from being converted to fat by the liver and stored. Increased sensitivity to insulin is a good thing but ironically not only do obese people make less adipotectin but half of the obese population is resistant to insulin anyway. And, the fatter they get the more insulin resistant they become.

Why are we programmed so well to get fat and stay fat? In an ironic twist, that which was created through evolution to preserve life against the previously constant threat of famine is now killing many of us. It seems those biologically enhanced to hoard fat and perpetuate life through historically frequent lean times are now, in the world of supersized meals and readily available high caloric processed foods, the ones most likely to die early.

The good news for the gravity challenged athlete is that the latest science still supports exercise and diet as the best approach to fat loss and the maintenance of optimum body weight. The old adage that weight gain occurs when caloric intake exceeds energy expenditure is still correct. This is, however, a more complex statement than it first appears. First, not all calories are dealt with the same way by the body. Researchers have found that those who consume more white bread, rice, pasta and other refined carbohydrates tend to add fat disproportionately around the midsection where others who eat about the same number of calories from foods like whole grains, beans, fruits and vegetables had little change in their waist measurements. It turns out body shape does matter.

People who are shaped like an apple, with excess body fat stored around the abdomen, are more likely to suffer diabetes and cardiovascular disease. Those shaped like pears with fat deposited in the lower body, ie., hips, buttocks and back have less health risk due to obesity. It is now known that the so-called “visceral fat” in the abdomen is more dangerous to ones health. Otherwise skinny people with a bit of a belly are more prone to health problems than they would like to recognize. It seems that visceral fat is more metabolically active and prolific at spewing toxic substances than subcutaneous fat which is deposited more uniformly over the rest of the body. These findings make sense of the observation that liposuction does little to reduce health risks. Although unsightly fat is eliminated through these increasingly popular procedures blood studies show no improvement in disease markers whereas someone who lost the same amount of weight through exercise and diet would experience improvements in cholesterol, blood pressure and insulin resistance.

The implication of the second part of the old adage is not straight forward either. The caloric expenditure associated with bouts of exercise is not as significant as the effects of regular exercise on increasing the metabolic rate. Regular low intensity exercise can train your muscles to burn fat better and create more muscle to burn more fat all the time. This increase in metabolic rate 24/7 is the true benefit of developing a very substantial base of aerobic fitness.

BASE TRAINING and the FAT BURN

When exercise is performed at low intensity, the slow twitch muscle fibers produce energy aerobically using fat as a primary energy source. Regular and prolonged low intensity exercise creates a demand for oxygen and an adaptation in the muscles to meet the energy requirements of such chronically practiced workouts. This adaptation involves a vast multiplication of the tiny cellular energy factories called mitochondria and the aerobic or oxidative enzymes housed within. In this way, after six to twelve weeks of performing low intensity BASE workouts, you can transform your metabolism and become a “better butter burner.” Your body will rely more on fat to produce daily energy requirements than ever before. In addition to the great health benefits related to reduced fat stores as discussed earlier, by stripping the anchor of fat away from your midsection you will perform better too.

Not only will the reduced body weight associated with long slow workouts improve your power to body weight ratio to propel you faster but these early season BASE training sessions create the absolute best foundation for your entire triathlon fitness program. Improving efficiency in fat metabolism has many advantages for the athlete. Fat burns clean and produces more energy per gram than carbohydrate or protein. Fat is in unlimited supply (even when you get lean) whereas carbohydrate availability is often the limiting factor in athletic performance. (Remember the Bonk?)

Most importantly fat metabolism produces less fatigue as compared to carbohydrate utilization with its corresponding production of lactic acid. Lactic acid is associated with fatigue and accumulates in the muscle cell as increases in exercise intensity shift muscle metabolism toward carbohydrate utilization. Proper Base Training creates the aerobically fit athlete whose ability to burn fat results in a leaner body better equipped to compete well. Proper base training insures that energy production at all levels of exercise intensity is derived, to the greatest extent possible, from fat. This aids performance by sparing valuable, but limited, carbohydrate stores staving off fatigue and improving power to body weight ratios. The key to making these workouts beneficial is to remember that after long slow workouts you don’t need to replenish carbohydrates as much as you would with high intensity training such as intervals or hill climbing. Since fat is the body’s preferred energy source for low intensity workouts a balanced post workout meal of protein, fat and carbohydrates would start the replenishment process well.