The first, and most logical, thing to learn about natural health and fitness is to eat for nutrition, rather than to simply fill your stomach. Eat foods that will provide energy, and boost metabolism. The concept is pretty simple, and once it is understood it becomes natural.
The human body thrives on nutrients. Our bodies reward us for nutrient rich diets by giving us more energy, higher metabolism, and a healthy physical appearance. Would you lube your vehicle engine with Pepsi? I assume your answer is no. Your vehicle would break down in a short period of time without the oil it needs to run smoothly. Think of your nutrient rich body as a well oiled machine.
When your stomach is filled with "filler foods", your digestive system does not work as hard, thus slowing your metabolism. When your stomach is filled with fruits, vegetables, whole grains and / or proteins, your digestive system is working at capacity, digesting and distributing nutrients. When your body becomes used to processing whole foods, your metabolism gets in to a routine of working efficiently and steadily. A strong metabolism translates to a "free pass" on OCCASIONAL indulgence foods, meaning that that cheesecake will pass trough your efficient digestive system relatively unnoticed.
A nutrient rich diet does not necessarily mean a complete overhaul of your current diet. Perhaps some simple substitutions would get your started. Whole foods are the important thing. That means replacing white bleached grained foods, such as white bread and white pasta, with the whole grain variety. Leaner meats, such as ground turkey rather than ground beef. More fruits and vegetables are important. Last but not least, drink plenty of WATER.
Remember, you are what you eat.