When are our best times to start and stop eating? This is an interesting and oddly understudied question that researchers are now starting to investigate. Today, the typical diet advice given usually revolves around what to eat and how much to eat. With most of the focus being on the total calories and macronutrient ratios. However, when we should eat is often seldom discussed. It turns out that when we eat is becoming a more fascinating area of study for nutrition, and for good reason. What researchers are finding is that when we eat could be as important as what we eat, and even by how much. What is known as “time restricted eating” is a time based approach to nutrition. What time restricted eating involves is deciding on a certain time of the day when you will start and stop eating. Calories are not restricted, just the time in which you can eat those calories is. This simple change in when we eat is surprising researchers because it’s proving to have remarkably positive results for weight loss and disease resistance.
Time Restricted Eating
A team of researchers fed two identical sets of mice a diet where 60% of their calories came from fat. This would be a diet similar to eating cheeseburgers, french fries and milkshakes for every meal (a.k.a the Standard American Diet). One set of mice were allowed access to unlimited food and could eat whenever they wanted. On average the mice ate a majority (half) of their food at night, while constantly nibbling throughout the day. The other group was restricted to eating during an 8 hour eating window, thus fasting for the remaining 16 hours. The two control groups ate a standard diet where only 13% of their calories came from fat under similar conditions.
“After 100 days, the mice who ate fatty food frequently throughout the day gained weight and developed high cholesterol, high blood glucose, liver damage and diminished motor control, while the mice in the time-restricted feeding group weighed 28 percent less and showed no adverse health effects despite consuming the same amount of calories from the same fatty food. Further, the time-restricted mice outperformed the ad lib eaters and those on a normal diet when given an exercise test.”
The results from this study are fascinating because it directly challenges our current weight loss paradigm. The typical advice given to people who are looking to shed a few pounds is to focus on restricting their calorie intake while also eating many small meals and snacks throughout the day. This study however, shows that perhaps a far more effective strategy would be to instead do the exact opposite. Forget about counting calories and/or spreading out your meals; instead focus on condensing all your meals into an 8 hour eating window.
Now, you’re probably thinking, “this research sounds interesting but i’m not a mouse… i’m a human.” Indeed you are. Although there has been similar research done on humans and it turns out that a lot of us tend to eat just like mice do.
In one study, through the use a smartphone app, healthy individuals were asked to record their eating patterns throughout the day. What they found was that most of the subjects ate frequently and erratically throughout the day. The majority of them ate for 15 hours or longer every day, while consuming a majority of their calories at night (sound familiar?). They then asked some of the overweight subjects to condense their eating patterns into a 10-11 hour window for 16 weeks. What they found was that “they reduced body weight, reported being energetic, and improved sleep. Benefits persisted for a year.”
Another human study that came out recently found similar results. They followed 11 overweight men and women and had them follow two different eating patterns. The first was from 8 am to 8 pm, which corresponds with the average american eating time. The second was from 8 am to 2 pm, which allows for an 18 hour fast every day. To eliminate subjectivity, the researchers had all participants try both eating schedules, eat the same number of calories both times, and complete rigorous testing under supervision. What they found was that despite calories being the same, the participants that were restricted to a 6 hour eating window experienced reduced daily hunger swings, fat burning during several hours at night increased and metabolic flexibility (the body’s ability to switch between burning carbs and fats) improved.
What this research is showing is that calories are once again, far less important than what we think. It also shows that allowing our bodies extra time to fast every day (known as a style intermittent fasting) seems to have many benefits with relatively zero downside.
The Effect of Nighttime Eating
Today, people usually eat their largest meals and a majority of their daily calories in the evenings. We tend to eat large dinners followed by a dessert and perhaps even the addition of some late night snacks and/or alcoholic beverages. Unfortunately, it turns out that late night eating and snacking can have a surprisingly large impact on our waistlines and quality of sleep.
One study that was done on people’s eating patterns that compared the effects of late night eating (having lunch after 3 pm) to early evening eating (having lunch before 3 pm) found that, “late lunch eaters lost less weight and displayed a slower weight-loss rate during the 20 weeks of treatment than early eaters.”
New research is also shedding light on how nighttime eating affects our quality of sleep. Researchers have found that melatonin (a hormone our body releases during the evening that makes us feel sleepy) and insulin (a hormone our body releases after we eat a meal that helps stabilize our blood sugar) are inversely related. This mean that when melatonin is high, our insulin levels will be low. If we spike our insulin levels (by having a late night snack or beverage for example) our melatonin levels will drop. This effect would make us feel less sleepy and could negatively affect our quality of sleep.
Having poor quality sleep not only makes us feel fatigued during the day, but it can also drastically affect our food choices and appetite as we go throughout the day. When we are sleep deprived we typically experience more intense cravings for high calorie, sugary foods. We can also experience more erratic and intense hunger swings throughout the day. These effects will typically lead to poorer food choices, more snacking, binge eating and ultimately overeating.
As you can see, late night eating could be a lot less innocent than it seems. Those late evening glasses of wine or bag of chips that you enjoy as you watch Netflix, could lead to slower weight loss, poorer sleep, more erratic appetite and cravings, inevitably cycling you through unhealthy eating habits.
Time restricted eating, which is also known as a style of intermittent fasting, is something that I have personally been practicing for many years now. This style of eating has lead me to amazing results and researchers are now proving the benefits that I have observed for quite some time. As the recap, these benefits include:
- Reduced daily hunger swings
- Increased fat burning
- Accelerated weight loss
- Improved sleep quality
- Improved energy levels
- Improved metabolic flexibility
If time restricted eating is something that you would like to experiment with, (which I highly recommend you do) my recommendation would be to pick an 8 – 9 hour eating window that works best for your current lifestyle. Eat the same amount of food you would typically eat, except do it all within the new eating window you’ve created.
As an example, here is what my typical daily eating pattern looks like:
- 7 am: a cup of coffee (I don’t count coffee, water or tea as breaking my fast)
- 12 pm: breakfast
- 4 pm: lunch
- 7 – 8 pm: dinner
You could also follow something like this:
- 8 am: breakfast
- 12 pm: lunch
- 4 – 5 pm: dinner
Since we all have different lifestyles and our bodies are all unique, we’re going to have different preferences. The good news is that time restricted eating is very flexible. You can easily experiment with different eating windows and find the one that works best for you.
The key to this protocol is not to restrict your calories, just restrict the time in which you consume those calories. Now, this isn’t a green light for you to eat as many Cheetos and tubs of ice cream as you want, this strategy is best used in combination with healthy eating habits. However, I know that sometime we can fall off the wagon. We get overly busy or stressed, and our diets suffer because of it. If you are having a difficult time eating healthy due to your current lifestyle, then time restricted eating can become an easy and effective strategy for you to mitigate some of the negative effects of a poor diet. We may not always be in control of what we eat but we are always in control of when we eat.
If time restricted eating sounds like something that you would like to experiment with, I would highly recommend starting by downloading my free Eat Differently Food Journal. With this daily food journal you will be able to:
- Set a 8-9 hour time window which would work best for you
- get a clear picture of your current diet
- track your daily added sugar intake
- pinpoint bad habits which you can then improve upon
- keep yourself accountable