Weight watchers are often confused as to the best course available to them to reduce or maintain their Body Mass Index (BMI) as every one knows about the disastrous consequences of BMI beyond 25. Any BMI beyond 30 is a distinct threat and warning for the onset of the much dreaded Obesity development and the consequent increased chance of morbidity. There are two distinct issues in this much discussed area of concern to people all over the world. Whether weight can be controlled by exercise alone or dieting is absolutely necessary or not. What does the science say?
It is simple logic that when input is more than out put the excess needs to be stored and same logic applies for weight gain also. Man needs about 2000 kC of energy for day to day maintenance and incremental growth and depending on the physical work, the energy need will increase proportionately. Olympian Mark Spitz, the unchallenged swimming ace is reported to be consuming a 10000 kC diet but as one can see he is a slim figure as most of the energy is burned during his work out. Nutritionally the food consumed directly goes for performing day to day work and if the stored body fat is to be eliminated to achieve weight reduction one must undertake rigorous physical activity to draw body fat as the energy source.
Imagine the energy expenditure for a 1000 meter walk which is less than 100 kC and if 5 kg body fat needs to be shed, one may have to walk at least 50 km without increasing the energy intake. But walking 50 km with a restricted diet requires determination and perseverance which very few people have. Therefore dieting with reduced calorie intake and moderate exercise only can succeed in weight reduction. The issue gets more complicated when the calorie expenditure in many individuals is much less than the ideal 2000 kC because of their sedentary life styles with minimum physical exertion. The basal metabolism to maintain the vital body functions requires 1200 kC and the actual daily calorie needs in many cases will lie between 1200 and 2000 kC. Therefore even a 2000 kc diet may be converting excess calories into body fat for storage in many people and consequent increased body weight gradually. The mistaken belief that exercise can reduce weight irrespective of what is consumed must be removed from the minds of weight watchers. It has been scientifically established that physical exercise has many benefits like strengthening of bones and muscles, lowering of blood pressure, improvements in mood and mental health, lowering of cholesterol levels, reducing risks associated with CVD, diabetes, breast cancer and colon cancer but expecting to reduce weight might not be realistic from normal exercise regimen.