Have you ever wanted to strangle someone who told you that they’ve found an easy way to lose weight? There’s no shortage of folks who promise big weight loss if we’ll just tweak our fat intake, eat fewer carbs, or wear some kind of space-age body wrap.
The current hope of the dieting world isn’t new; it’s just newly popular. Intermittent fasting (IF) has been gaining momentum amongst those with weight-loss goals because, when done right, IF can deliver results. Plans vary, but they all include some pattern of fasting and non-fasting periods. A faster’s gameplan may include fasting on two days in every seven (5:2), fasting on alternate days, or eating only within an eight-hour window each day. While eating healthy food is encouraged, the main focus of IF is not what someone eats, but when.
Studies have claimed that IF improves insulin sensitivity and beta cell function, lowers blood pressure, dampens evening cravings, and can help with weight loss. A Newsweek article cited claims of IF reducing cancer risk and increasing life expectancy. But other sources are quick to caution people about the potential harms of IF, especially for people with diabetes.
It’s tempting, when sources offer conflicting opinions, to just forget the whole thing and grab a handful of chips. But though IF is fast achieving fad status, the real risk and benefits aren’t that hard to figure out once you take a step back and remember basic nutrition rules.
For those with diabetes, the potential benefits have to be carefully weighed against the very real risks.
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How It Works
Much of the research on the benefits of IF has been done on animals, with a few small human studies. The strongest health claims for IF are that the diet reduces inflammation, improves insulin sensitivity and other disease markers, and promotes weight loss.
One explanation for some of the health benefits is that fasting puts the cells under mild stress, and then the cells adapt once the fast is broken. Cells get stronger just as muscles get stronger in response to periods of stress and rest.
There may also be benefits from prompting the body to dip into its fat stores. Once carbohydrates stores are depleted, the body will burn fat for energy and release fatty acids and ketones into the blood. This process may have some benefit for the brain, though it also poses risk for those with diabetes (more on that later).
However, most sources agree that the real benefit of intermittent fasting comes from reducing calorie intake. Reduced calorie intake has been linked to health benefits in mice, even if no weight is lost. And IF often does lead to weight loss, so long as someone doesn’t overeat during the non-fasting phases. Weight loss is absolutely associated with reduction in disease risk, improved insulin sensitivity, and improved cardiovascular health.
It’s not clear which health benefits of fasting are associated with fasting itself, and which are simply a product of the resulting weight loss.