In a trial involving fasting those who ate no food at all for 36 hours then returned to regular eating patterns for 12 hours lost more than 7 pounds within a month, and their immune systems remained stable after 6 months.
According to the researchers from the University of Graz the benefit behind alternate day fasting may be due to the adherence to hunter gatherer patterns of eating from thousands of years ago when food was not readily available each day, but they note this may not be suitable for everyone and additional studies are needed to validate long term safety.
According to Valter Longo of the University of Southern California, fasting 4-5 days at a time can lower cholesterol, blood pressure levels, and decrease the likelihood of cardiovascular disease; after 48 hours of fasting the body will exhaust glucose reserves and will turn to other energy sources. First it will use fat stores then muscle, at this point organs will start to break down. By reaching a 5 day fast a mass of cells die leading to a decrease in bad components such as excess glucose, IGFI, and triglycerides. Once you start eating the body will regenerate new cells, and the old cells will be replaced with healthy ones.
Fasting does carry a few risks such as hypoglycemia and heart palpitations, as well as those taking certain medications for diabetes or high blood pressure are at an increased risk for hypotension. Those aged 70+, or those with anorexia should never fast at all. Anyone considering fasting should seek professional medical advice and consult with their physician before fasting to determine if it is safe for them.
A study published in the journal Cell Metabolism involving 60 participants who were divided into a control group or an alternate day fasting group, and who all kept food diaries while being under continuous glucose monitoring reached an average calorie restriction of 35% and lost on average 7.7 pounds after 4 weeks.
“Why exactly calorie restriction and fasting induce so many beneficial effects is not fully clear yet,” says Professor Thomas Pieber, head of endocrinology at the Medical University of Graz. “The elegant thing about strict ADF is that it doesn’t require participants to count their meals and calories: they just don’t eat anything for one day.”
“The reason might be due to evolutionary biology. Our physiology is familiar with periods of starvation followed by food excesses,” says Professor Frank Madeo.
An additional 30 subjects were put on an alternating day fasting schedule for 6 months to assess the safety of the diet over a longer period, which yielded positive results. After 6 months immune function in the subjects appeared to be stable, and they had a reduction in belly fat, as well as decreased levels of triiodothyronine which is associated with lifespan in previous research.
Many find consistent calorie restriction of dieting hard to maintain and will often succumb to yo-yo dieting, these findings may help to shift the debate over dieting to the favor of intermittent fasting.
“We feel that it is a good regime for some months for obese people to cut weight, or it might even be a useful clinical intervention in diseases driven by inflammation,” said Professor Madeo. “However, further research is needed before it can be applied in daily practice. Additionally, we advise people not to fast if they have a viral infection, because the immune system probably requires immediate energy to fight viruses. Hence, it is important to consult a doctor before any harsh dietary regime is undertaken.”
