The Atkins diet gained a modicum of respectability this month when scientists reported that two clinical trials found the high-fat, high-protein, low-carbohydrate diet did not cause disastrous increases in serum cholesterol and even reduced one or two cardiac risk factors.
The studies, reported in The New England Journal of Medicine, compared the effects on weight loss and cardiovascular risk factors of the Atkins scheme with the conventional low-fat, low-calorie diet recommended by most health experts. Both diets resulted in weight loss, but participants on the Atkins diet lost more weight, faster.
But it is too soon to jump on the Atkins bandwagon in hopes of achieving bathing-suit slimness by the Fourth of July. Yes, the diet does help obese people lose weight quickly, and those wanting to shed 5kg in the next four weeks could achieve that goal. But the research suggested that by Labor Day many, if not most, are likely to be back to their starting weight.
The first 2kg to 3kg lost on Atkins are not fat but water, released by the body when it gets little or no starch or sugar from food. So as soon as you are unable to resist that bun with your burger or summer's succulent sweet corn, a cooling ice cream cone, thirst-quenching watermelon or a bag of fries, those lost kilos are likely to come bounding back.
Neither of the new studies was designed to determine either long-term safety or effectiveness of this regimen, which puts foods like bread, pasta, rice, potatoes, carrots, tomatoes, corn, bananas, winter squash, dried beans and peas, cereal and, of course, ice cream, cake, cookies, pies, sweet rolls, doughnuts, candy and bagels on the don't-eat-them list and suggests instead indulging in bacon and eggs, steaks and cheese, cream (but not milk) and butter instead.
The predictions were that this diet would spell disaster for the heart and blood vessels. But the new studies showed for the first time in randomized clinical trials that there may be some cardiovascular benefits to this high-fat regimen.
As expected when people lose weight, cholesterol levels did not rise (indeed, they fell in some participants) and, as expected when the diet contains little sugar and refined starches, triglyceride levels fell. Insulin sensitivity also improved -- again, no surprise when limited carbohydrates are consumed.
Perhaps the only surprise finding among Atkins participants was a rise in the so-called good cholesterol, protective HDLs, which may indicate that the body compensates for a diet rich in saturated fats and cholesterol by producing more of the substance that helps to keep arteries clear of fatty deposits.
As noted in the editorial accompanying the reports, the two studies, which involved obese or severely obese participants, were short-term. (One lasted six months and the other a year.) About 40 percent of the participants dropped out of the studies and were lost to follow-up. In other weight-reduction studies, dropouts are usually people who fail to lose weight or regain their losses. It nearly always means that they did not stay on the diet.
Among those who did stay in the programs, the differences in the amount of weight lost on the two diets were not drastic and, in the one-year study, those following Atkins starting gaining weight back after six months, resulting in no significant weight-loss differences between the two diets by the end of the year.