You've all read, I am sure, about how crucial it is to limit the amount of insulin your body secretes after eating. It's why you're advised to consume meals and snacks that are high in complex carbs and protein and low in simple carbs.

It's also why a fad diet that's been around since the Great Depression started being seen as something more than a fad diet in 2004. In January of that year, the Scripps Clinic released the results of a 12-week study performed with grapefruit and grapefruit juice, one of the key elements to the Hollywood Diet that first appeared back in the 1930s and later morphed into the Grapefruit Diet.But instead of having dieters subsist on grapefruit, small salads, lean meat and coffee, as per the original variation, the researchers in 2004 had subjects continue eating the way they had been, but some added half a grapefruit to main meals. Others drank grapefruit juice with breakfast, lunch, and supper. And, as usual, a control group changed their habits in no way.While the researchers did admit that the subjects probably did a bit more exercise than prior to the study, that increase couldn't have been the only reason why some who started consuming grapefruit lost more than 10 pounds in 12 weeks. Overall, the average loss for those eating grapefruit was 3.6 pound; the juice-drinking group, 3.3.Researchers theorized that some component in grapefruit was reducing the release of insulin that follows every meal. When a poorly constructed meal calorie laden or not causes excess insulin to be secreted, the chance that a sizable portion of that meal gets stored as fat skyrockets, whether or not the body needs immediate energy.Excessive secretion of insulin was not occurring in those using grapefruit, it seemed, meaning those people were using their consumed calories more effectively as energy. A more recent study validates that something in grapefruit reduces body fat storage.Researchers at the University of California-Berkeley created high-fat and low-fat diets for lab mice and studied four variations of them. One group consumed a high-fat diet and pulp-free grapefruit juice; another, the same diet, but sweetened water of the same caloric value replaced the grapefruit juice. This pattern was replicated with two groups on a low-fat diet, and a fifth group served as the control group.What researchers found after 100 days was significant. Compared to the mice that ate the high-fat diet and drank the sweetened water, the mice on the high-fat diet that drank the grapefruit juice gained 18 percent less weight.Furthermore, the mice eating the high-fat diet and drinking sweetened water instead of grapefruit juice secreted three times more insulin.While the mice on the low-fat diet drinking grapefruit juice weighed the same as those on the low-fat diet drinking the sweetened water, their insulin levels were only half of what the sweetened-water group recorded, suggesting that weight gain would occur in the sweetened-water group eventually.The researcher then compared a compound found in grapefruit and known to have an effect on blood sugar levels, naringin, with a commonly used drug that's prescribed to do the same, metformin. When administered to the mice, the substance naturally found in grapefruit was as effective as the drug at controlling blood sugar levels.Interestingly enough, using the naringin as a drug and not as part of natural grapefruit juice did not cause any weight loss, causing the researchers to infer that it's a synergistic effect created by multiple compounds in grapefruit juice rather than a sole element that affects insulin secretion.While the researchers cannot definitively determine why the grapefruit juice possesses such fat-neutralizing properties, there seems to be some connection to consuming the stuff and fat storage.In fact, in a follow-up study, the researchers used obese mice, and yet the average weight of the mice drinking the grapefruit juice instead of the sweetened water along with the high-fat diet was 8 percent less after 55 days. And, as in the first study, the grapefruit-juice group demonstrated lower blood sugar levels and better insulin sensitivity.For those who are skeptical about the research shared here, consider what's known about coffee. In the hundreds upon hundreds of studies performed on it, it's clear that consumption of it, especially on an empty stomach, increases the rate at which you burn calories, which seems to be primarily the result of caffeine. Yet, consuming coffee has been linked to a number of other health benefits where the caffeine cannot be the only cause.Clearly, it's a combination of dozens of antioxidants and who knows what else that have allowed researchers in certain studies to record a lower incidence of type 2 diabetes, stroke, and certain cancers in those who consume coffee than in those who do not.