Intermittent fasting is becoming increasingly popular to lose weight without counting calories. With its popularity, has come criticism about whether fasting is an effective way to lose weight. To offer clarity, researchers from the University of Illinois Chicago debunked four common myths about the safety of intermittent fasting.
Intermittent fasting is a type of time-restricted diet where fasters leave a long gap between their last meal one day and the first of the next. It doesn’t specify which foods to eat, it focuses on when you’re eating them.
Whilst many research institutes find intermittent fasting a safe diet, several myths continue to circulate. The researchers looked into four popular myths and debunked them using clinical studies and data.
“I’ve been studying intermittent fasting for 20 years, and I’m constantly asked if the diets are safe,” said lead author Krista Varady, professor of kinesiology and nutrition at UIC. “There is a lot of misinformation out there. However, those ideas are not based on science; they’re just based on personal opinion.”
Debunking four popular myths
There are two main types of intermittent fasting. One method is alternate-day eating, people alternate between days of eating a very small number of calories and days of eating what they want. With time-restricted eating, people eat what they want during a four- to 10-hour window each day, then don’t eat during the rest of the day. The researchers conclude both types are safe despite the popular myths.
The researchers debunked four myths that are gaining traction.
Intermittent fasting does not lead to a poor diet
The researchers looked at studies showing the intake of sugar, saturated fat, cholesterol, fibre, sodium and caffeine do not change during fasting compared with before a fast. And the percentage of energy consumed in carbohydrates, protein and fat doesn’t change, either.
Intermittent fasting does not cause eating disorders
None of the studies showed that fasting caused participants to develop an eating disorder. However, all the studies screened out participants who had a history of eating disorders, and the researchers say that those with a history of eating disorders should not try intermittent fasting. The researchers urge paediatricians to be cautious when monitoring obese adolescents if they start fasting because this group has a high risk of developing eating disorders.
Intermittent fasting does not cause excessive loss of lean muscle mass
The studies show that people lose the same amount of lean muscle mass whether they’re losing weight by fasting or with a different diet. In both cases, resistance training and increased protein intake can counteract the loss of lean muscle.
Intermittent fasting does not affect sex hormones
Despite concerns about fertility and libido, neither oestrogen, testosterone nor other related hormones are affected by fasting, the researchers said.
