Is Fasting Effective for Weight Loss?
There is also a growing trend of celebrities and doctors promoting various fasting formats for weight loss, detox, and lifespan extension. Is there any truth to these claims?
Let’s begin by clarifying: fasting can be a very dangerous approach to weight loss, because prolonged caloric restriction can lead to severe health problems and even death. When you don’t eat, your body is starved not only of calories, but nutrients that are essential for cellular metabolism. The dangers are especially high for teens and young adults, who may also develop eating disorders.
Looking into scientific literature, there have been studies showing that intermittent fasting may be effective for weight loss.
In one experiment, researchers tested if intermittent fasting could be a more reasonable strategy than prolonged starving, experimenting first with yeast, then mice, and later humans. In the human study, 19 middle-aged participant were selected for a 3 month trial. For 5 days a month, subjects would consume just 35% of their normal caloric intake. If 2000 calories were consumed in a normal day, a “fasting” days would allow only 700 calories.
After 3 months, the subjects were compared to a control group that continued eating normally. Those who intermittently fasted showed a reduction in risk factors linked to diabetes, cancer, and heart disease. There was also a slight reduction in visceral fat which led to a 3% body weight loss. The diet achieved the goal of caloric reduction without negatively impacting micronutrient intake.
Another study conducted on 107 obese women over 6 months compared 2 days of “fasting” and 5 days of regular caloric intake with a standard weight-loss diet. The 2 “fasting” days allowed for an intake of 600 calories. Both strategies ended up leading to similar weight loss of 13 pounds, and improved bio-markers. For some people, 2 days of suffering, with 5 days of eating normally may be more feasible compared to watching calories every single day.
Should you try a fast-mimicking diet? It seems like the answer is highly individual, but like all diets, unless you can maintain it for years, you will lose weight and then bounce right back up to were you started. A much healthier approach is to simply change your lifestyle and food types. In any case, if you want to try a fasting diet, do it only under medical supervision.