What time did you eat your dinner last night? Chances are it was at 7 or even 8 p.m. And what about your breakfast? If your days are long, it is likely you grabbed a coffee or a piece of toast pretty early in the day. As the scientific evidence linking intermittent fasting to hormonal control and weight loss has grown so, too, has interest in prolonged periods of time within each day that we actually do not eat. Forget calorie counting or limiting your carbs — weight control may be as simple as eating across fewer hours each day.
The 8-Hour Diet proposes that limiting your food intake to just eight hours of the day is an easy diet technique that supports weight control. This way, all calories and meals need to be consumed within just eight hours of the day — for example, brunch at 10 a..m, lunch at 1 or 2 p.m. and your final meal of the day by 6 p.m. The amount of calories or even fat consumed is not important — rather, it is argued that our long days, in which food may be consumed across as many as 16 hours each day, is one of the key reasons so many of us are struggling with our weight.
Indeed, there are some physiological aspects of this argument that make sense. Prolonged periods of feeding, in which food is not only consumed relatively frequently, every few hours and across many hours of the day means that more insulin (the hormone that controls blood glucose levels) is released in an attempt to keep blood glucose levels stable. High levels of insulin over time promote inflammation and fat storage in the body. In addition, hunger is less likely to be experienced, as we never really let ourselves get really hungry and fat is more likely to be stored in the liver.
Studies on animals support this approach when it comes to weight loss and hormonal control. In some preliminary studies, rats given free access to high-fat foods but only for relatively short periods of time weighed less, and had no issues with their cholesterol levels, blood glucose levels or inflammation in the liver. On the other hand, rats given free access to food across 24-hour periods gained weight, developed high cholesterol and high blood glucose as well as impaired motor control. Researchers concluded that constant feeding results in the body going into storage mode — gaining weight and placing stress on the liver, which in turn results in increased blood glucose levels. On the other hand, when we stop eating for a number of hours, the liver stops releasing glucose into the bloodstream and instead uses it to repair the body’s cells, which in turn reduced inflammation. In addition, cholesterol is more likely to be broken down rather than stored.
So what does this mean for us? There is more evidence building to show there is a number of health benefits associated with not eating for a number of hours, from both a hormonal and weight perspective. In real life, though, this is easier said than done with long hours and shift work resulting in meals and snacks being consumed at all times of the day and night. The environment in which we live also encourages food consumption constantly, regardless of hunger or meal time.
While the exact period of time in which metabolic benefits are experienced from not eating is unknown, it appears that leaving at least 12 hours per day without food is beneficial, and at an extreme 16 hours each day. In real life terms, this means a later start to the day food-wise, and consuming your final meal by 8 p.m. at the latest. Another option if your day starts early is to eat breakfast as normal, eat your main meal at lunchtime and then have a light snack by 6pm. This way you still have 12-14 hours without food each day but are still eating enough calories so you do not experience extreme hunger throughout the evening.
The biggest issue with diets that limit calories in some way is that extreme hunger is then experienced which makes compliance challenging. The key thing with fasting is that for it to work you need to not eat anything, whereas in real life little extras slip in which negate the benefits. As such, for the 8 Hour Diet to be effective, you will need to consume a substantial meal at some point during the day so that your hunger does not get the better of you.