Intermittent fasting, including not eating for 16 consecutive hours, is often recommended for weight loss. On the TikTok social network, the hashtag #jeuneintermttent has more than 92 million views.
The book “How to Fast” says that fasting releases natural healing forces in addition to being a treatment and anti-aging. Dr. Èvelyne Bourdua-Roy, co-author of the book and family physician certified in obesity medicine, answered our questions.
How to start intermittent fasting? Is it effective for weight loss? What are the effects on the body? Depriving your body of food for a period of time has become more democratic in social networks. Some apply it as part of a “detox cure”, others to lose weight or as a spiritual experience.
According to Dr. Èvelyne Bourdua-Roy, co-author of “How to fast”, published by Thierry Souccar, fasting allows good metabolic health.
From Montreal, the founder of Clinique Reversa, a non-profit clinic for the transformation of chronic diseases related to lifestyle based on low carb diet and fasting, answered questions from ETX Studio .
Are there different forms of intermittent fasting?
You need to start by recognizing fasting” including intermittent fasting from a restricted eating window. Most people who talk about intermittent fasting are talking about skipping breakfast and eating two meals within a a window of about 8 hours or less.
For example, we eat at 2 pm and have dinner at 8 pm. We didn’t eat anything until 2pm the next day. The eating window is between 2 pm and 8 pm, and the no-feeding or fasting window is between 8 pm (after the last meal of dinner) and 2 pm the next day. This is called “restricted eating window” or TRE (Time Restricted Eating), but people often call it “intermittent fasting”.
This is different from true fasting which is a hormonal metabolic state where blood sugar levels are low, blood insulin levels are low, and the liver’s stores of sugar (glycogen) are empty or almost empty. At this time, the body makes a kind of seesaw and different changes in “mechanics” occur. The time of this transfer varies from individual to individual, but usually it is about 18 to 36 hours.
Whether we’re talking about a limited eating window (which many people call intermittent fasting) or actually talking about a physiological state of fasting, there are some interesting benefits for metabolic health. For example, fasting lowers blood sugar (blood sugar) and insulin (blood insulin). If practiced regularly, it helps to reverse insulin resistance and all the diseases that accompany it, such as type 2 diabetes and idiopathic high blood pressure.
How many hours a day should you fast in a day to reap the benefits of intermittent fasting?
To determine how many hours to fast per day or per week, one must first have an idea of insulin resistance or current metabolic health, determine one’s goals, and establish what is feasible. and interested to do. You should also consider your body mass index (for example, people with very low body fat should fast for less time and less often than people with an index that is above normal, for example ), the medications you are taking (there are contraindications or medications that require close monitoring and possible adjustments) and your general state of health (it is not recommended to fast during pneumonia in antibiotics, for example).
There is no universal recipe, and that’s good. Finding your own fasting pattern and practicing it regularly allows you to reap the benefits of fasting and maintain it over time.
Is intermittent fasting effective for weight loss?
It can be done, but it depends on the people. We found considerable inter-individual variation in our patients and participants. There are several reasons why fasting helps to lose weight: the metabolic shift that promotes a physiological state of catabolism and lipolysis (burning of body fat stores), the balance of hunger and satiety hormones after fasting, improving insulin sensitivity (insulin is the master hormone of fat storage, so the more you hide it because you are resistant, the easier it is to store fat and difficulty burning it), reducing calorie intake, etc.
Fasting, unlike low-calorie diets, does not lower the basal metabolic rate. It even made a slight increase in the duration of the fast. By the way, we examine many misconceptions or myths about fasting in “How to Fast”, along with the relevant science.
However, if fasting is done by a person with an eating disorder or food addiction and they lose control of their food after their fast, it will not be effective in losing weight and will harm the person’s mental health. . . Fasting is not immediately defined or at least not if it is of long duration.