Diet plans that incorporate intermittent fasting are popular, but are they healthy? The verdict is mostly still out on the long-term effectiveness of adding periods of fasting if you are trying to lose weight or get healthier — or experience a “body cleansing,” as some proponents of fasting label it.
Some studies have shown that intermittent fasting can have benefits. But other studies have shown that simply eating smaller meal portions more frequently throughout the day can be effective for weight control and establishing an efficient metabolism, which is key for keeping the pounds off and preventing chronic conditions, including heart disease, diabetes and some cancers.
Metabolism refers to the myriad of chemical reactions that takes place in the body’s cells. Metabolism converts the food we eat into the energy needed to function in our everyday lives. The “metabolic rate” refers tot he speed at which the body burns up calories. The slower your metabolism, the more likely you’ll gain weight and keep it off.
The bottom line: No one should attempt a diet that includes intermittent fasting without consulting their primary care physician. Your doctor will likely have you consult with a dietitian as well. There have been studies that show some forms of short-term fasting can help regulate blood sugar and help with weight lost.
But longer-term fasting, such as not having meals every other day, may be problematic. Fasting every other day has been found to help some people lose weight in the short-term, but its long-term effects haven’t been studied sufficiently, said a scientific statement [1] from the American Heart Association earlier this year. “There is evidence that both alternate-day fasting and periodic fasting may be effective for weight loss, although there are no data that indicate whether the weight loss can be sustained long term,” researchers concluded.
The best results from fasting, including weight loss and improved glucose (blood sugar) control, occurs when skipping meals is part of a strict schedule without variating, says Natacha Borrajo, a registered dietitian with Baptist Health Primary Care [2].
“Intermittent fasting needs to be very regimented,” says Ms. Borrajo. “It cannot be about fasting here and there or fasting all the time to lose weight. That doesn’t work. Fasting over long periods of time can slow down your metabolism and you can’t lose weight with slow metabolism. So fasting has to be regimented.”
An example of such regimented fasting would be eating meals from 10 a.m. to 6 p.m., providing the body with a period of 16 hours of fasting. But caution is recommended by doctors and dietitians when it comes to larger time-frame fasting, such as fasting for one or two days out of the week.
Medically supervised intermittent fasting has shown to help increase insulin sensitivity, which helps regulate blood sugar control — and that’s a big must for diabetics.
“If you’re a diabetic and you’re going to try intermittent fasting, you’re going to have to be checking your blood sugar regularly,” says Ms. Borrajo.
Aggressive reductions in calories can help reverse type 2 diabetes, a new study has found. Eating between about 850 calories a day for three to five months put the disease into remission in almost half of diabetes patients in the study — but fasting was not part of the reduced-calorie diets. Nonetheless, restricting calories or fasting is an increasingly popular method of tackling diabetes.
The AHA’s scientific statement affirmed what Ms. Borrajo recommends: any fasting should be regimented and supervised. “Irregular eating patterns appear less favorable for achieving a healthy cardiometabolic profile,” researchers emphasized. “Intentional eating with mindful attention to the timing and frequency of eating occasions could lead to healthier lifestyle and cardiometabolic risk factor management,” they said.
And, of course, always get your check-up and let your doctor know if you want to try a substantial dietary change or weight-loss program.
“You don’t want to take on any new diet without consulting your physician and learning about any adverse effects from intermittent fasting,” says Ms. Borrajo.