Can you take a five-day “vacation” from your low-carb diet every week and still burn fat? A new study suggests that possibility.
Researchers here found women who cut carbs for just two days each week lost more weight than women who stuck with a permanent calorie-restricted diet. In other words, for five days every week, the low-carb groups ate what they wanted and still lost weight.
The study, presented at the San Antonio Breast Cancer Symposium, randomly assigned 115 women with familial histories of breast cancer (in other words, they’re considered high risk) to one of three diets for four months.
- One group ate a 1,500-calorie Mediterranean-type diet.
- The second group ate their normal diet, but two days a week they cut carbs and also calories to about 650 on those two days.
- The third group also ate as they pleased and low-carbed two days a week, but without any caloric restrictions.
Just to clarify, during these two low-carb days, researchers allowed the two groups 50 grams of carbohydrate. They could eat one piece of fruit each day as well as non-starchy vegetables. I say this because studies fluctuate wildly over what they define as a low-carb diet.
Besides weight loss, practicality was a big reason researchers chose this diet. They wanted a diet these women at high risk for breast cancer could stick with long term.
All three groups lost weight. But whereas the low-calorie Mediterranean group lost an average of five pounds, both low-carb groups almost doubled that loss with a nine-pound average weight loss.
Now, if you’re a low-carb devotee or even tried this diet for a short period of time, your response to this study is likely Duh! Of course the low-carb groups would do better. You’ve seen firsthand how effectively this diet can be for fat loss.
And then you reason if they had done low carb every day, rather than two days a week, that weight loss would be even better.
Indeed, this study proves how powerful a low-carb diet really is. Even though these intermittent low-carb groups ate Zeus knows what on their “off” days, they still lost more weight than the other group who cut their calories every day.
Another interesting observation in this study is that both low-carb groups had improved insulin and leptin levels compared to the Mediterranean group. Both hormones have linked to breast cancer risk.
A study in the Journal of the National Cancer Institute, for instance, concluded high insulin levels increased breast-cancer risk in postmenopausal women.
Insulin is also the key to why these low-carb groups lost more weight. I don’t care how low you restrict your calories. (Actually, I do, but that’s a different article.) The point is, every time you eat carbohydrates, you raise insulin levels. And insulin does one thing really well: it stores fat.
With a low-carb diet, on the other hand, you don’t have those blood sugar spikes and crashes. You keep insulin levels balanced, which decrease your risk for breast cancer and, as these women discovered, helps you better burn fat.
Intermittent low-carbing might work for people who want to “flirt” with low-carb but can’t bear the thought of sacrificing pasta or cheesecake.
But the take-home here is not to eat low-carb two days a week and then load up on whatever junk foods you want the other days. Besides being effective for fat loss, a low-carb diet packed with vegetables, lean protein, low-glycemic fruits, and nuts and seeds is the healthiest, most nutrient-rich diet you can eat.