The scientifically proven benefits of intermittent fasting
In the past few years intermittent fasting has gained a lot of traction in the health scene, with popular blog articles written about it in major publications such as the New York Times and The Guardian. However the scientific community has been exploring the health benefits of short term fasting for several decades, with the first paper on the subject dating back to 1988. Since then, scientists have determined many factors that make intermittent fasting both a powerful weight loss technique as well as a tool for improving overall health.
On the surface, the weight loss from intermittent fasting seems intuitive; skipped meals means less calories taken in during the week. While this is true, and a part of the weight loss potential from intermittent fasting, it was also found that intermittent fasting triggers biological digestive responses that can accelerate weight loss even quicker than a standard calorie deficit.
A study in the Journal of Endocrinology showed that men who had fasted for 18 hours experienced decreased insulin levels and increased growth hormone production, both of which are known factors in how the body creates and processes fat. Lower insulin levels causes the body to be less likely to store sugars and carbohydrates as fat, and high growth hormone means the body is more likely to turn to its fat stores to burn for energy. While not changing the overall metabolic rate, it seems that intermittent fasting leads the body to prioritize using fat stores as energy, making it a useful tool in permanent weight loss.
There are also some much more far broad and extraordinary potential benefits of intermittent fasting, although those have not been tested in human trials. A 2008 study found that alternate day fasting resulted in longer lifespans for mice; even those who consumed the same net calories per week and had the same bodyweight as control groups had lower glucose and insulin levels and were more resistant to endotoxic stress. It also found that monkeys who were on an overall calorie restriction had lower levels of insulin and of oxidative damage. However, the authors were also quick to note that caloric restriction during the formative years of monkeys or humans is unethical, and may hinder important mental and physical development. They also noted that “While improved health and increased longevity are enormously attractive to most people, it seems unlikely that people would find the idea of reduced caloric intake sufficiently attractive to actually undertake the regimen”.
Indeed, the greatest hindrance to intermittent fasting as a common health regimen seems to be its difficulty to maintain. To see any of the hormonal benefits the diet needs to be followed quite strictly, which requires a great amount of planning ahead and inflexibility, something not often afforded to busy people or those with families. Also, professionals such as Dietitian Amy Langer note that “People with any history or predisposition to eating disorders or disordered eating of any kind should not attempt this diet” as it can trigger dangerous eating habits. While intermittent fasting is definitely a useful health and diet tool, it is ultimately a situational and short term tool.