Myth or Reality: Intermittent Fasting
Intermittent fasting has become a very popular topic in recent years, whether for weight loss, health optimization, or even longevity. But what does science really tell us about it?
What is intermittent fasting?
Intermittent fasting involves alternating between periods of fasting (where no calories are consumed) and periods of “normal” eating. There are various formats: some people choose to fast for 16 hours a day, while others prefer to fast for 24 hours, once or twice a week.
During normal periods, our bodies draw energy from glucose (from carbohydrates). During prolonged fasting, when glucose is depleted, the body turns to other reserves, mainly fat, to produce the energy it needs to function.
What are the potential benefits?
Some studies, mainly conducted on animals, suggest that intermittent fasting may have certain positive effects:
Weight Loss
In humans, intermittent fasting may promote some weight loss, but this is no greater than that achieved with a low-calorie diet with equivalent energy intake.
Body Composition
In mice, an improvement in the lean mass/fat mass ratio is sometimes observed.
Cardiovascular Health
Some animal studies have demonstrated possible improvements in markers of heart health.
Aging
A few animal studies have explored a link between intermittent fasting and slowing cellular aging, but data in humans is still very limited.
What we Must Keep in Mind
Despite its popularity, intermittent fasting is not a miracle solution. There are still several gray areas in the scientific literature:
- Most of the beneficial effects have been observed in animals, and very few rigorous studies have been conducted in humans.
- The long-term effects are still largely unknown.
- Maintaining this type of diet is often difficult, particularly over several months or years.
What About Hunger in all This?
It is normal to feel hungry every 3 to 4 hours. This is a natural signal from our body, and repeatedly ignoring it can:
- Disrupt our hunger and satiety signals
Lead to a lack of energy - Impair our concentration and performance (both mental and physical)
In conclusion, intermittent fasting is not necessarily bad, but it is not miraculous either. It may be suitable for some people in the short term, but it should be practiced with caution, and ideally under the supervision of a healthcare professional, especially for people who are active, have health problems, or have special nutritional needs.
Listening to your body and eating a balanced, varied diet tailored to your needs remains the best approach... in the long term.
Savard, V. (2023, July 19). Le Jeûne intermittent: Diabetes Québec. Diabète Québec. https://www.diabete.qc.ca/en/le-jeune-intermittent/