Low-Carb Beats Low-Fat for Heart HealthPosted on Aug 9th 2010 12:00PM by Jonny Bowden
Here's what happened.
Researchers took 307 participants and randomly divided them into two groups. One went on a very low-carb diet, which was right out of the Atkins playbook. For three months these folks consumed no more than 20 grams a day of carbs from fibrous, low-glycemic vegetables (exactly what the first, and rather strict, "induction" phase of the Atkins four-stage approach calls for).
For each week after the initial three months, this group then added back in 5 grams per day of carbs. In other words, the first week (after the initial three months) they consumed 25 grams of carbs, the second week 30 grams, and so forth.
Other than carbs, this group had no restrictions and could eat all the protein and fat they wanted. They kept this up till they reached a desirable weight and were able to stay there. In other words, standard, textbook Atkins.
The second group went on a standard low-fat diet between 1200 to 1800 calories a day. The only "restriction" was to keep fat to 30 percent or less of calories (standard advice).
The researchers were primarily interested in weight loss and they found there was no difference in weight loss between the two groups. But don't think for a minute that's all there is to this story.
You may recall that the traditional rap on low-carb diets is that they may work in the short term for weight loss, but some people claimed they are dangerous.
So the researchers had a secondary outcome, meaning there was something else besides weight loss that they wanted to look at -- risk factors for heart disease. Many people claimed that low-carb diets like Atkins may actually raise the risk of heart disease for the dieters who replaced bread with bacon. But in this study, that was not the case.
Six months into the study, the low-carb group had a greater reduction in diastolic blood pressure, a triglycerides and a particularly bad form of "bad" cholesterol called VLDL (very low-density lipoproteins).
And -- hold on to your hats - at all time points throughout the two-year study, including at the finish line, the low-carb group had a significant increase in HDL ("good") cholesterol.
Overall, the weight lost by both groups wasn't enormous -- 22 pounds in the first year (average for both groups), with both groups regaining some during the second year and averaging about 15 pounds after the two-year study.
This isn't surprising. Virtually every study I've ever seen has found that people start reverting to their old habits to some extent, which is why they gain some weight back. The more they slip back into their old ways, the more they gain back. No surprise there. The individuals who were able to stick with their program gained back the least amount of weight, or even continued to lose weight-- - the averages don't tell us that.
It took six months for the low-carb group to see improved cardiovascular risk factors, but that after that, there was no difference between the two groups in those risk factors -- both had improvements.
That's not surprising either, and I would consider that likely evidence that the low-carb group started drifting more towards "conventional" eating after six months, thus wiping out the differences between the low-carb and the low-fat group.
If you had your choice between two diets, both of which produced weight loss, but one of which did it with less hunger and better cardiovascular outcomes, which would you choose?
Don't buy for a minute that this study shows "no difference" between low-fat and low-carb. It doesn't. It showed no difference between groups in the weight loss department, but a greater improvement in cardio risk factors for the low-carb group.
That ain't chopped liver!
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Jonny Bowden, author, nutritionist and weight loss coach, cuts through all the misconceptions about diet and fitness to help you transform your body, your health and your life. Visit his website to learn more.