As anyone in the nutrition field is aware, there are plenty of extreme dietary practices. Personally, I’ve heard about everything from the baby food diet to the Dukan diet to something about alkaline blood levels. Usually, these extreme dietary practices are met with an eye roll, knowing that these outrageous diets will last about as long as an avocado in it’s prime. But what if there was a dietary trend that promised long-term health benefits that focused not necessarily on what you eat, but when you eat?
Intermittent fasting is any period of voluntary food restriction. Protocols are varied and might include religious fasting, time restricted feeding (i.e. eating all calories within a short time window) or scheduled days of extreme caloric restriction (i.e. ≤ 25% of energy needs) followed by normal or high calorie days.
I am always skeptical of any diet or dietary pattern that claims to fix everything from obesity to cancer, but – bro-science aside – intermittent fasting is gaining a substantial amount of attention in research. A recent and thorough review in The Annual Review of Nutrition concluded that intermittent fasting might be a viable strategy to benefit overall human health, including improvements in biomarkers associated with chronic disease. Notably, however, most human research studies are limited by small sample sizes, lack of control groups, insufficient follow-up, and inclusion of normal weight or healthy individuals who are unlikely to respond to interventions.
The best diet for optimal health is one that is maintainable. A large (n=100) and long (1 year) study in metabolically healthy obese adults published last year found that drop-out was highest in the group randomized to alternate-day fasting. The long-term adherence to intermittent fasting and applicability to public health is therefore questionable.
Diet quantity and quality will always be paramount for the promotion of optimal health and healthy aging. For me, I couldn’t live without my morning matcha latte and eggs… but maybe breakfast isn’t the most important meal of the day, at least for habitual non-breakfast eaters.