I’m sure that at least a few of you have heard or read about the latest trend in weight loss called “intermittent fasting.” The very word “fasting” is probably less than appealing, as it pretty much means you don’t eat or drink anything (except perhaps water) for a specified amount of time. Starvation is not exactly recommended among health professionals. But intermittent fasting is different. Is it something you should try?
What is intermittent fasting, anyway?
Intermittent fasting has been the talk of the town, so to speak, thanks to two recent books to hit the market: The Fast Diet by Dr. Michael Mosley and Mimi Spencer, and The Overnight Diet by Caroline Apovian, MD. Intermittent fasting essentially means that you skip a meal or severely restrict calories on certain days of the week with the intention of losing weight, controlling blood glucose, and/or decreasing heart disease risk. But on the other days of the week, you can pretty much eat what you want (within reason, of course). For many people, this concept sounds appealing. Limiting calories for a couple days a week doesn’t sound that bad if you can eat what you want the rest of the time.
The Fast Diet, also called the The 5:2 Diet has you eat between 500 and 600 calories (women get 500 calories, men get 600 calories) for two days out of the week, spread over two meals of about 250 to 300 calories. These fast days should not be right in a row, and your food choices ideally should be more plant-based and emphasize protein. The premise is that after several hours of fasting, the body burns up its carbohydrate stores and shifts to burning fat for fuel. Many claim that intermittent fasting also helps to blunt appetite.
The Overnight Diet emphasizes getting enough sleep; a lack of sleep can disrupt metabolism, making it hard to lose weight. Sufficient sleep, according to the author, will reduce hunger pangs. The diet part of this involves drinking homemade smoothies once a week, and eating a low-calorie, high-protein diet the remaining six days of the week.
Does intermittent fasting work?
In many ways, these two diets sound like just another fad to come around the bend. And maybe they are. However, there actually is some credible science behind fasting. Restricting calories in the diets of animals appears to increase their lifespan, for example. Recently, a team of researchers in the UK looked at the various approaches to intermittent fasting, with a focus on how they might help (or hinder) those with Type 2 diabetes and obesity. They found that intermittent fasting is as effective as or even more effective than simply cutting calories to lose weight.
They also found that intermittent fasting has other health benefits, including reducing inflammation, lowering blood pressure, lowering heart rate, lowering cholesterol, and reducing insulin resistance. This unique approach may even help prevent the development of Type 2 diabetes. Followers of the diet also believe that intermittent fasting can prolong your life and prevent Alzheimer disease.
Is intermittent fasting for you?
Sound appealing? Before you jump on the intermittent fasting bandwagon, realize that not a whole lot of research has been done in this area, at least with humans. The few studies thus far look promising: In one study, fasting was shown to lower blood pressure and cholesterol, and on “regular eating” days, the subjects did not overindulge, which has been a concern. But again, we still don’t know a whole lot about intermittent fasting.
Wondering what you might eat? A sample 500-calorie menu from The Fasting Diet is steel-cut oatmeal with ½ cup blueberries for breakfast, and then chicken stir-fry made with 5 ounces of chicken and some vegetables, along with a tangerine for dinner. That’s it. Would that hold you?
Could intermittent fasting be harmful? Well, that depends. If you take insulin or sulfonylurea drugs to control your blood glucose, intermittent fasting can considerably raise the risk of low blood glucose unless you make appropriate adjustments. This way of eating is not suitable for pregnant women, people under the age of 20, people who are underweight, and people who have an eating disorder. It may also not be good for people who take certain types of medicines, such as beta-blockers.
Another question to ask yourself: Can you stick with this way of eating? It may sound simple to just eat 500 calories for two days a week, but 500 calories isn’t all that much. On those days, you’re likely to feel tired, grumpy, anxious, and irritable. You also may not sleep well and your breath might not exactly smell like a bed of roses.
But, if you’d like to give intermittent fasting a try, talk it over first with your health-care provider and decide together if it’s something that could work for you. And if you have tried this, feel free to share your experience!