You may be able to lose weight and extend your life in the process — without giving up your favorite foods.
Researchers at Washington University in St. Louis are studying whether fasting for a few days a week is easier than counting calories daily, and whether fasting helps with weight loss and slows aging.
This is not an absolute fast, because it does not require you to give up food for the entire day. Instead, Dr. Luigi Fontana, a researcher at Washington University in St. Louis, says to aim for 500 calories on a fasting day. The rest of the week, participants are allowed to eat normally.
Based on studies of rodents and monkeys, researchers believe intermittent fasting has the same effects on weight loss as chronic caloric restriction, which Fontana said means reducing caloric intake by 15 to 25 percent a day. Intermittent fasting may also have life-extending qualities that help prevent Type 2 diabetes, heart disease and Alzheimer’s.
Fontana, a research professor of medicine, is leading a study with about 40 participants who are either overweight or slightly obese. Half of those studied will fast intermittently for 12 months. The other half will eat regularly for six months then begin intermittent fasting for the last six.
Already, some are seeing results in their weight. Poonam Bhandari, a senior scientist at Washington U., has lost 10 pounds since January. Her body mass index, which is a measurement of body fat based on height and weight, was slightly above 28 at the start. The Centers for Disease Control and Prevention says a BMI of 25 to 29.9 is considered overweight. Three months later, Bhandari’s BMI has dropped to 25.8.
Kathleen Obert, the registered dietitian on the study, said Bhandari’s results are not unlike those of many other participants. Bhandari, 52, was instructed to begin by fasting three days a week. Her weight dropped quite rapidly, though — about 2 pounds a week — so researchers quickly reduced her fast to two days.
On fasting days, Bhandari has only tea for breakfast with no milk. At lunch she has about 1 ½ cups of steamed vegetables, and at dinner about 2 ½ cups. She said she drinks a lot of water for a fuller feeling through the day.
At night, Bhandari admits, she sometimes feels a bit lethargic after fasting. And on evenings before a fast, she occasionally overindulges. But overall, she believes the diet is easier than counting calories on a daily basis. She’s even sure she could sustain this lifestyle for the long-term.
“My friends, they all kind of already started on it by themselves because they thought this was a pretty nice way of doing things,” she said.
Actually, a lot of people want to try it. The diet is already very popular in the United Kingdom.
Shohreh Jamalabadi-Majidi, clinical research coordinator, said she’s received an overwhelming number of requests to participate in the study, especially from women, and there’s a long waiting list.
Fontana said he believes the study is so popular because people are excited the diet only affects their eating habits for a few days a week. Still, a few people have dropped out because they can’t handle the changes.
On fast days, participants are instructed to eat only non-starchy vegetables. They can have one large portion in the evening or two smaller portions, for lunch and dinner. If they make a salad, they may have up to two tablespoons of olive oil a day, which are 100 calories each, and as much vinegar as they want.
“At the beginning, it can be difficult because people, especially in the U.S., they think they are always hungry, and they want to have always something in their hand to drink or to eat, but I think it’s psychological,” he said.
Yet for the most part, study participants have successfully stayed in the program. Obert said the majority complete more than 85 percent of fasts in a month.
“I was thinking people would have a harder time doing it,” she said. “I’ve been nicely surprised.”
Fasting does have its critics, though. Some worry that it can lead to obsessing over food, which can in turn lead to an eating disorder. Fontana said participants are carefully screened to make sure they have not had an eating disorder in the past.
Participants could also experience fatigue and a temptation to overindulge on non-fasting days, which Bhandari has experienced. But she said she has not noticed other concerns, such as mood swings, nausea and difficulty sleeping.
Participants take multivitamins to avoid nutrition deficiency, and they’re encouraged not to exercise on fasting days.
Still, there’s just not enough research to prove that intermittent fasting can extend a human’s life.
That’s where Fontana comes in. While his research does track weight loss, the real intention is to study the effects of fasting on aging. Participants are being tested at various points in the study to track metabolic and cardiovascular effects.
Fontana also hopes to do a study in the future that would incorporate a Mediterranean diet on top of fasting.