Is Intermittent Fasting Really Effective?

Kathryn Adel June 3, 2019 Diabetes, Eat Well, Health, Heart Health, Weight Loss

3. Effects of intermittent fasting on weight loss

According to the meta-analyzes and systematic reviews conducted to date, intermittent fasting can promote weight loss and fat loss, including visceral fat reduction, as well as the maintenance of muscle mass during weight loss. These effects seem to be comparable to those of a continuous diet with caloric restriction.

It has been stipulated that intermittent fasting can decrease the secretion of insulin and thus increase the body’s ability to burn fat. However, it would seem rather that the weight loss resulting from intermittent fasting is caused by the fact that intermittent fasting decreases the opportunity to eat, which decreases the total amount of calories consumed per day.

Some studies suggest that intermittent fasting can have a favorable effect on the basal metabolism (amount of calories burned per day by the body in order to survive) during a weight loss process by mitigating its decrease, but not all studies demonstrate this effect. Further studies are needed to better understand the effects of intermittent fasting on basal metabolism.

It should be noted that not all studies show that intermittent fasting is an effective method of losing weight. For example, one study compared the effect of intermittent fasting versus daily caloric restriction in 23 obese women. The women followed a diet with traditional caloric restriction for 12 months, followed by intermittent fasting for 15 hours a day for one month (they could eat at will the rest of the time), then returned to a traditional calorie restriction for 11 months, for a total of a two-year study period. During the month of intermittent fasting, the rate of weight loss decreased significantly compared to the months of traditional caloric restriction (weight loss of 1.25 kg per month during caloric restriction versus 0.47 kg during the month of intermittent fasting).

Is it necessary to deprive yourself of eating to be healthy?

Intermittent fasting can be an effective method for some people to lose weight, improve blood glucose control or improve lipid profile. However, it is highly likely that a reduction in calorie intake through a balanced diet leads to similar results. Intermittent fasting can be difficult to follow depending on your schedule, workouts or social activities. If a diet is too hard to follow, it cannot be sustained in the long run. To improve your health or lose weight, the best diet is the one you can follow in the long term!

For some, it can be reassuring to impose a food plan with strict rules such as intermittent fasting, but the reality is that it is not necessary to deprive oneself of food in order to be healthy. In addition, the experience of having external rules that dictate how one should eat distances us from the signals of hunger and satiety sent by our body. There are already solutions to eat well without having to restrict oneself, including re-learning to listen to our body.

In conclusion, there are not enough studies to confirm that intermittent fasting is an eating style that will improve your overall health. With regard to weight loss, there is no evidence that intermittent fasting works better than a conventional caloric restriction. Without it being declared better than other diets, it may still be followed by certain people more likely to practice intermittent fasting than a restrictive diet on a continuous basis. However, these procedures should be practiced under the supervision of qualified health professionals such as a physician and/or dietitian, who can help monitor blood glucose levels and adjust medications as needed.

References

• Extenso (2018) Le jeûne intermittent pour mieux contrôler le diabète. http://www.extenso.org/article/le-jeune-intermittent-pour-mieux-controler-le-diabete/
• Headland et coll. (2016) Weight-Loss Outcomes: A Systematic Review and Meta-Analysis of Intermittent Energy Restriction Trials Lasting a Minimum of 6 Months. Nutrients; 8(6):354
• Seimon et coll. (2015) Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials. Mol Cell Endocrinol; 15;418 Pt 2:153-72.
• Harris et coll. (2018) Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. JBI Database System Rev Implement Rep; 16(2):507-547.
• Aksungar et al (2017) Comparison of Intermittent Fasting Versus Caloric Restriction in Obese Subjects: A Two Year Follow-Up. J Nutr Health Aging;21(6):681-685.
• Tinsley et Horne (2017) Intermittent fasting and cardiovascular disease: current evidence and unresolved questions. Future Cardiology; 14 (1): 47-54.
• St-Onge et coll. (2017) Meal Timing and Frequency: Implications for Cardiovascular Disease Prevention. A Scientific Statement From the American Heart Association. Circulation; 135(9): e96-e121.
• Trepanowski et coll (2017) Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese Adults: A Randomized Clinical Trial. JAMA Intern Med; 177(7): 930–938.
• Cioffi et coll. (2018) Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials. J Transl Med;16(1):371.
• Sundfor, Svendsen et Tonstad (2018) Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial. NMCD; 28(7): 698-706.
• Zauner et coll. (2000) Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine. The American Journal of Clinical Nutrition; 71(6): 1511–1515.

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Author

Kathryn Adel

Kathryn holds a Bachelor Degree in Nutrition as well as a Bachelor and a Master Degree in Kinesiology, all from Laval University. She is a Registered Dietitian and active member of the Ordre professionnel des Diététistes Nutritionnistes du Québec (ODNQ) and of the American Academy of Nutrition and Dietetics. She holds the Monash University's certification for the FODMAP diet and IBS, and has considerable clinical experience in that area. She is also an accomplished athlete, having ran track and cross-country at a national level. Kathryn specializes in sports nutrition, weight loss, diabetes, as well as heart and gastrointestinal health.