Originally Posted by alcanoe

BluesDawg is on target. Much of nutrition science is bogus and that's particularly true for that which appears in the popular media. I've spent over $200 on contemporary college level exercise/nutrition vs health and human performance physiology books over the last several years and have not seen anything like that.

While the number of fat cells do stay relatively constant, it's their size that changes apparently. There certainly are genetic variations that affect how certain people can gain weight more than others. But the rash of fat people over the last several decades is not do to an epidemic of genetic mutations. Two major factors are the removal of physical activity from the work place and the availability of processed food designed to appeal to our natural desire for fatty/salty/sweet tastes.

However, it is more than just calories in vs calories out. The body processes carbs about 15% less efficiently than fats. So replacing fat intake with carbs can in theory cause a loss of body fat for the exact same activity level. But, one needs to keep a reasonable balanced diet which seems to be 50% calories from carbs, 20% protein and 30% fat with saturated fat limited to no more than 10% of total calories. That appears to be the present thinking. On those 100 mile days and possibly a few after, the carbs would likely need to be higher to replenish the glycogen.

I can post references if anybody is interested.

As an after thought on the personal choice point, some of the reasons for our fat epidemic are commuting, the TV, PCs and supersizing of meals, particularly in restaurants. My wife and I have split menu items. Using an exercise bike or rowing machine works for viewing some TV. They have actually determined that you burn fewer calories while watching TV than when you are asleep. Brain dead I guess.

Another biggie is the loss of muscle mass with age (about 1%/year before 70 and about 3% after for the sedentary) and the subsequent reduction of calories burned at rest. Weight training is essential, even for cyclists to stay healthy with ageing. Then too, one does need to cut calories as one ages as well. A Reasonably balanced diet as mentioned and a strenuous exercise program allows one to do that with out being hungry all the time.

Al