Exercise and Weight Loss
Several times a year I am asked by participants if, through our exercises, they can:
- Lose (fat) weight
- Lose fat in specific areas with special exercise
They also ask or discuss (or argue about) various diet and supplement questions.
The short answers are:
- Yes, but diet is much more important, and
- No, probably not.
The Long Answer
Exercise is an activity in which the body does work -- either by moving itself or other object. This is accomplished through the provision of electrochemical signals from the brain commanding various muscles to contract. Muscle contraction consumes energy. This energy is stored in a form called Adenosine triphosphate (ATP), which is found throughout the body. Enough "free" ATP is present in most muscle cells to last for about 3 seconds of exertion.
Energy is stored in the ATP molecule. When a phosphate atom is split off, energy is released and you are left with phosphate and Adenosine diphosphate (ADP). To get more ATP, the body either steals it from somewhere else in the system, or goes through a chemical process of creating it. Exercise triggers the body to produce more fuel utilizing available resources. Three different mechanisms are used to do this, depending on the intensity and duration of the exertion:
- Phosphagen system (provides full "bursting" power, available for a few seconds)
- Fast glycogen system (lasts 1 - 2 minutes, about half of your bursting power)
- Slow glycogen system (lasts until you run out of fuel, about 1/4 - 1/3 of your bursting power)
The phosphagen system depends on the presence of creatine phosphate within the muscle cells. The body chemically separates the phosphate from the creatine, and combines it with another chemical (ADP) to create ATP-fuel for use by the muscle cells. As this is done, the creatine phosphate level within the tissue declines. This process can supply nearly 100% output for about 8 - 10 seconds before depletion.
Fast glycogen system depends on the presence of glycogen within the muscle cells and liver. The body converts the glycogen to glucose, and then coverts the glucose to ATP (with the byproduct being lactic acid). This process cannot produce ATP as rapidly as the phosphogen process, and lactic acid is the byproduct.
After about 45 seconds of exertion ATP generation shifts over to the slow glycogen system. The body continues to utilizes remaining glycogen in the muscles, from the liver and blood, and through food digestion within the intestines, to produce glucose. But the final steps in the process involve oxygen from respiration and the byproducts are carbon dioxide and water. The rate of energy production is much lower than the phosphagen or fast glycogen processes, but can continue for much longer, basically until you simply run out of fuel sources.
Most of our energy comes from the food we ingest. Nutrition and digestion are immensely-complex topics. To grossly oversimplify them relative to exercise, we can roughly categorize the relevant food types as carbohydrates, sugars, fats and proteins. Carbohydrates and sugars (glucose) are converted to glycogen for storage in the liver and muscles. Fats are converted to glycerol and fatty acids which get distributed via the bloodstream to provide energy and other cellular needs. Proteins are broken down into various amino acids and re-arranged by the body to build and repair tissues as needed.
Glycogen reserves are generally the body's first choice for general fuel resources. As these are depleted, the body shifts over to fat reserves. A great amount of energy can be reserved in fat, but the transition from glycogen to fat -- referred by some as "hitting the wall" -- can be quite unpleasant, and will take different amounts of time depending on your particular body, the amount of glycogen present, rate of consumption, etc.
Some people naturally, or through diet modification, reduce the glycogen stores thereby inducing their bodies to tap into fat reserves sooner, if not just as a general practice. Doing this requires minimizing the intake of foods that result in glycogen, specifically carbohydrates. An indicator that this is happening is the odor given off during exercise and perspiration. Many people describe it as smelling like acetone, alcohol or kind of sweet. The metabolic state is called ketosis, and there is some controversy regarding whether ketosis is healthy as a long-term metabolic state (if at all).
Depending on diet and other factors, the body may also begin to consume amino acids (the building blocks of protein) to create ATP. An indicator that this is taking place is an ammonia smell in the sweat. It indicates that the rate of energy consumption has exceeded the availability of glycogen and fats, and that the body is tapping into readily-available amino acids at a rate exceeding the kidneys' abilities to filter the byproducts out of the blood. It isn't necessarily a bad thing, but can usually be avoided by adding more fats and carbohydrates to the diet.
Whether any of these metabolic states are healthy, hazardous, will make you grow additional limbs, become stupid or sterile, etc., is a matter of debate.
The counter-intuitive part now arises: Many people cut down on fats and increase carbohydrates to try to cut weight. Instead of eggs and bacon for breakfast they have a bagel with low-fat cream cheese. However, consumption of sugars (glucose) and carbohydrates, especially refined carbohydrates, can rapidly increase blood glucose levels. This stimulates the pancreas to produce insulin. Some studies indicate that a higher insulin level in the body prompts it to store energy as fat, rather than as glycogen. This dynamic can lead to unexpected body fat and weight gain, even when the person is exercising and dieting in an attempt to reduce weight.
That all being said, while exercise is effective for conditioning muscles, joints and building overall system robustness, exercise alone is rarely effective for weight control. Diet -- how much and what you eat -- is a much larger factor.
Also, while exercise can tone the muscles in specific areas of the body, I do not know of any exercises that target fat in specific body areas. Where your body chooses to store fat is based primarily on gender, age and other factors.
It is worth noting that the body image ideals put forth by the media are unrealistic for most people and probably unhealthy. A little body fat is not a bad thing.
My personal preference is to try to get nutrients from the foods that I eat. Unless someone has a physical problem, this should be possible by choosing a variety of foods consisting primarily of vegetables and meats (and other fat and protein sources), and secondarily, fruits and grains (carbohydrates). A thorough analysis would include blood studies to see if there are deficiencies to be addressed. I'm not that thorough, but knowing my own diet, and having studied this a bit, I have made the following supplementations to my own diet:
- Routine fresh vegetable juice consisting of a variety of kale, collards, spinach, parsley, ginger, carrots and apples for general vitamin and enzyme needs
- Cod liver oil, primarily for vitamin D and oils
- Vitamin B complex drops, because my diet is likely low in vitamin B (liver is a good alternative natural source, but I don't care for the taste)
- Creatine for energy bursts and strength building (also available in red meats and fish, but would require eating about a pound a day)
- Glass of red wine (or some chocolate) for zinc and for other reasons
I think I'm getting enough general carbohydrates, protein and fats through basic consumption, so I rarely supplement them. I probably consume way too much suger due to a longstanding addiction to hazelnut mochas.
Others prefer to use vitamin supplements to achieve the same goals and many claim to have experienced good results by doing so. I'll grant that it is probably much easier to just take a pill or two once a day than go through the trouble of juicing a bunch of vegetables, adding B drops, creatine, etc. My own (entirely unresearched) theory is that I may be getting some benefit from the raw vegetable juice -- perhaps e-coli? -- and other natural sources that might not be present in a processed tablet. But in all honesty, I have no research to back up that theory.