In the spring of 1973, one professor of human physiology taught his students at Mount Holyoke College to be skeptical about the value of eating mass amounts of negative calorie products. He did not use that term, because it had not yet entered the general vocabulary. He also did not mention those foods now considered to be typical of negative calorie foods. Instead that professor usually focused on the lack of nutrients in a basic salad food. He cautioned his students about the inability of lettuce to deliver an appreciable number of nutrients.

One day he had mentioned what he thought would happen if someone were locked in a room full of lettuce. He had speculated that such a trapped individual would be forced to eat nothing but lettuce. He had further speculated that the lettuce would fail to provide the trapped soul with adequate nutrition. That was as close as he ever came to making a reference to negative calorie products.

At the present time, a similar professor could find much information about negative calorie products on the Internet. Such a professor might want to have his class discuss the potential benefit from eating those same products. Such a professor might hope to convince his students that all foods have at least a few calories. Such a professor might care to suggest that exercise had proven to be better than negative calorie products at helping a man or woman to reduce the circumference of his or her waist line.

Perhaps a present-day physiology teacher would invite his or her students to offer comments on the value of green tea. While not a negative calorie food, green tea is said to have the ability to raise the metabolism within the human body. The Epigallocatechin Gallate (ECGC) in green tea is supposed to act in much the same way as do negative calorie products. It causes the body to draw on the energy in the body system. In other words, it forces the body to tap into the energy in the body fat.

As can be seen from the above paragraphs, negative calorie products can take-on several different forms. Such products could appear in the form of a green lettuce leaf, or they could appear in the form of green tea. While those two foods may seem quite different, they share a couple important features. Neither food could provide the body with needed nutrients. Neither food should be the primary ingredient of any diet. Both foods could be called negative calorie products.

Packaged negative calorie products can offer a benefit not found in the above-mentioned foods. Packaged negative calorie products normally contain caffeine. The caffeine gives the body an added energy boost. That boost is important, because the use of negative calorie foods can serve to drain-off a good deal of energy.

Still, even with the added caffeine, it is unwise to rely on negative calorie products while trying to loose weight. Such products do not offer added iron, a mineral that women should consider to be essential. In fact, that Mount Holyoke professor often reminded his female students that women should keep their bodies well-supplied with iron.