If you ask the average American what they'd like to change about their daily lives, they'll invariably say "lose weight" and "improve health". Modern pharmaceuticals have tried desperately to meet that desire with amphetamine-based diet pills or treatments like Alli (which I personally absolutely do not recommend). The problem that most people experience, however, stems more from a complete break-down in understanding how food is processed in the human digestive system than from any naturally occurring deficiency in some designer chemcial.
While the food industry is partially responsible for the epidemic of malnutrition in the US (in particular), there is also a potential break-down starting with the ubiquitous Food Pyramid. Recent study, research, and practice is telling us that those wacky guys at the FDA really do have it all wrong.
Health is based in nutrition, and nutrition is based in the foods you ingest - but you are not "what you eat". You are what you digest.
All foods require a specific reaction from the body in order to break down and digest them. Proteins (meat, eggs, etc.) require a highly acidic reaction from digestive enzymes while starches (bread, pasta, rice, etc.), fruit, and sugars require an alkaline (base) reaction. If you remember anything from grade school about chemistry, it's probably that acids and bases cancel each other out (sometimes violently) when such reactions have catalysts applied, such as the famous volcano experiement commonly seen at science fairs. (As a side-note, using the same baking soda, vinegar, and salt mixture can also clean out blocked or slow drains safely.)
The same kind of thing happens in your stomach when you eat foods that require opposite digestive reactions. The enzymes cancel each other out, so they produce extra gas and discomfort (think about how you feel after the huge Thanksgiving dinner) and also don't get around to digesting food with any efficiency. So, your food just sits there.
While it sits there in your stomach, the useful nutrients are processed out since they're usually the more soluble parts, but nothing is moving, so the process continues and ends up also pulling out the non-soluble parts like harmful fats and toxins. In the cases of proteins and sugars (especially fruit), the environment in the stomach is perfect for allowing other harmful reactions such as fermentation and putrefaction, and, yes, that's just as yucky as it sounds.
It's already common knowledge that eating several small meals a day is healthier all around than eating one or two big meals a day. One of the best ways to use food combining is to stick to this small meal plan and only put certain foods together:
"Going on a diet" is usually the first mistake than anyone makes when they are trying to accomplish a goal such as weight loss. Food combining is more about making a significant lifestyle change that will not only help you lose extra weight but will help you maintain a healthy weight and enjoy a greater level of health. By approaching any kind of dietary adjustment with a focus on making long-term changes instead of trying for short-term gains, you do yourself a much greater service inside and out.