How can it be? A dieting concept that is more than 80 years old and should have been laughed out of existence now suddenly may have some validity. The concept is grapefruit juice. My mother-in-law went on the grapefruit and lamp chop diet in the early 1930s (lamp chops were a lot cheaper then) to lose weight before her wedding. She told me about it years later, and wistfully recalled how quickly the weight came off.
Listening to her, my unspoken, but cynical take on this (she was my mother-in-law, so of course I did not say anything) was that restricting food intake to two or three items always causes weight loss. Boredom and even intestinal discomfort usually occur after a couple of weeks, if not sooner, and often the choice not to eat seems preferable to consuming, yet again, another grapefruit or well-done chop. Of course the weight came back, but that is true of most diets.
But the dieting world wasn't done with grapefruit, even if my mother-in-law, after her wedding, was. It kept on popping up as a fat-burning food despite the lack of any credible research to support the claims. The Depression and WWII interfered with further promotion of grapefruit as a weight-loss stimulator. First, people didn't have enough to eat and later, during the War years, rationing and limited food supplies must have made any dieting effort seem irrelevant and nonsensical.
But leaping ahead to the l970s, we find grapefruit emerging as the star food of the Hollywood Diet, or the Mayo diet, supposedly endorsed by the Mayo Clinic, which disdained to have anything to do with this fad. But here again, the diet was all smoke and mirrors. Of course the dieter would lose weight eating grapefruit at every meal. The dieter would have lost weight eating raw rhubarb at every meal. Only 800 calories a day were allowed on the diet, and like the Atkins program later on in the century, no carbohydrate was allowed. Only meat was okay to consume, although probably the cost of lamb chops was high enough so hamburger was substituted.
But the search went on for that elusive something in grapefruit that in some people seemed to promote more weight loss than expected from their daily calorie intake. It is known that grapefruit contains the chemicals naringin and hesperidin that have antioxidant activity. Could these be responsible for some unanticipated weight loss?
A study published in the journal Metabolism in 2012 by Dow, Going, Chow and others set out to answer conclusively whether grapefruit contained a potent weight reducer. The results were inconclusive. Overweight subjects who ate a half a grapefruit before each meal did not lose any more weight than control subjects who were not allowed to eat any grapefruit. Total cholesterol and the bad kind of cholesterol, LDL, decreased in the grapefruit group, as did their waist measurement but the differences were not statistically significant. However, the smaller waists of the subjects indicated that they might have lost belly fat, which is important in terms of cholesterol and blood pressure levels.
So is grapefruit moribund as a weight-loss activator? Apparently not. My mother-in-law may have lost weight not just because she became nauseated at the thought of eating another lamb chop and piece of citrus. Or to be precise, grapefruit juice now seems to be a potent inhibitor of weight gain if you are a mouse who loves to eat fat.
A few days ago, a group from University of California, Berkeley reported that mice that were fed a high-fat diet and drank pulp-free grapefruit juice gained 18 percent less fat than fat-eating mice that drank water. The grapefruit drinkers also had healthier glucose, insulin and triacylglycerol (a type of fat) levels in their blood. The study, conducted by Andreas Stahl and Joseph Napoli, was published in Plos One, a highly reputable online journal.
The mice were fed a diet that would have made Dr. Atkins weep with joy: it contained 60-percent fat and they ate it for 100 days. Mice in the fat-eating control groups were given water rather than grapefruit juice, and other groups were put on a healthier low-fat diet and given either the juice or water. And finally, the chemical naringin, which was assumed to be the reason people lost weight eating grapefruit, was given to two other mice groups also fed either high-fat or low-fat diets.
Against their expectations, the researchers found that the mice eating massive quantities of fat and drinking grapefruit juice gained substantially less weight than the water drinking, high-fat fed mice. Mice eating the more typical mouse-like, low-fat diet (mice normally do not feast on very fatty foods. They prefer grains, seeds and nuts) did not show much of a change in their weight regardless of what they were drinking. And naringin had no effect at all on decreasing weight gain.
These results perplexed the researchers, especially after they looked for typical explanations as decreased absorption of the food, increase in activity, and perhaps the fact that eating mostly high-fat food made the mice less hungry. None of these factors was responsible for the decrease in weight gain.
Obviously, human studies along with more animal studies must be done to find out how the juice from a particular citrus fruit could prevent weight gain on a diet that otherwise would provoke it. But this first report certainly raises intriguing possibilities.
Might a weekend of eating whipped cream-topped chocolate mousse and sausage, bacon and cheese omelets with butter drenched toast prevent the scale from imploding if you drink grapefruit juice along with your meals? Regardless of the answer, you can be sure that weeks from now there will be advertisements on the Internet promising magical grapefruit juice pills that will do just that.