The Skinny on Intermittent Fasting — Intermittent fasting (IF) is a weight loss approach that has been around in various forms for ages, but was highly popularized in 2012 by BBC broadcast journalist Dr. Michael Mosley’s TV documentary Eat Fast, Live Longer and book The Fast Diet, followed by journalist Kate Harrison’s book The 5:2 Diet based on her own experience, and subsequently by Dr. Jason Fung’s 2016 bestseller The Obesity Code.
Fung successfully combines plenty of research, his clinical experience, and sensible nutrition advice, and also addresses the socioeconomic forces conspiring to make us fat. He is very clear that we should eat more fruits and veggies, fiber, healthy protein, and fats, and avoid sugar, refined grains, processed foods, and key is to stop snacking.
According to Harvard Health Blog, IF makes intuitive sense. The food we eat is broken down by enzymes in our gut and eventually ends up as molecules in our bloodstream. Carbohydrates, particularly sugars and refined grains are quickly broken down into sugar, which our cells use for energy. If our cells don’t use it all, we store it in our fat cells as, well, fat. But sugar can only enter our cells with insulin, a hormone made in the pancreas. Insulin brings sugar into the fat cells and keeps it there.
Between meals, as long as we don’t snack, our insulin levels will go down and our fat cells can then release their stored sugar, to be used as energy. We lose weight if we let our insulin levels go down. The entire idea of IF is to allow the insulin levels to go down far enough and for long enough that we burn off our fat.
Initial human studies that compared fasting every other day to eating less every day showed that both worked about equally for weight loss, though people struggled with the fasting days.
New research is suggesting that not all IF approaches are the same, and some are actually very reasonable, effective, and sustainable, especially when combined with a nutritious plant-based diet.
We have evolved to be in sync with the day/night cycle, i.e., a circadian rhythm. Our metabolism has adapted to daytime food, nighttime sleep. Nighttime eating is well associated with a higher risk of obesity, as well as diabetes.
Just changing the timing of meals, by eating earlier in the day and extending the overnight fast, significantly benefited metabolism even in people who didn’t lose a single pound.
In a nutshell…
Avoid sugars and refined grains. Instead, eat fruits, vegetables, beans, lentils, whole grains, lean proteins, and healthy fats (a sensible, plant-based, Mediterranean-style diet). Let your body burn fat between meals. Don’t snack. Be active throughout your day. Build muscle tone.
Consider a simple form of intermittent fasting. Limit the hours of the day when you eat, and for best effect, make it earlier in the day (between 7 am to 3 pm, or even 10 am to 6 pm, but definitely not in the evening before bed). Avoid snacking or eating at nighttime, all the time.