Raspberry ketones, a dietary supplement that has become part of the latest diet fad, has some people scratching their heads over just what ketones are.

Everybody knows to monitor sugar, fat, carbohydrates and calories in a diet, but ketones?

When a body is starving for sugar, ketones take over and help breakdown the next best source of energy: stored fat.

The body produces ketones during starvation or fasting and also during long bouts of physical training. When your muscles are sore after strenuous exercise - ketones cause the pain.

Without ketones, there would be No Pain, No Gain. That's because ketones are acidic and typically become buffered by the amount of carbon dioxide in the blood.

During ketosis, the body becomes overloaded with the chemical and has more ketones than it knows what to do with.

The raspberry ketone diet is based on the premise that adding ketones to your diet will make your body release fat from fat cells. The ketones come from raspberry and have been used for years in the food industry as an additive in soft drinks, ice creams and sweet treats.

However, during starvation, the body also has low levels of sugar and insulin.

This combination of low insulin, and relatively normal glucagon and epinephrine levels causes fat to be released from the fat cells, according to the Diabetes Teaching Center at the University of California, San Francisco.

What does diabetes have to do with ketones? Diabetes can cause a buildup of ketones due to the body's lack of insulin and is one of the reasons why diabetic patients become comatosed.

Ketones haven't been clinically test or approved by the Food and Drug Administration for clinical purposes, but clinicians are testing other uses for ketones.

One clinical trial is looking into whether ketones can help block neurodegeneration in patients with Parkinson's disease.

Another trial is examining how manipulating ketones through diet can affect patients with pancreatic cancer undergoing chemoradiation treatments.

Tests in mice show promise for raspberry ketones. Researchers in Korea fed mice raspberry ketones and found that the supplement increased fat breakdown.

Sources: UCSF, Bodybuilding.com.