How Much Does the Timing of Your Meals Affect Your Weight?
It’s about damn time we talk about how the timing of your meals affects your weight.
Over the past few years, time restricted eating, or using its trendier name: intermittent fasting, has risen in popularity amongst dieters. But what is it exactly and how is it supposed to help you with weight management? Intermittent fasting is a diet that restricts your feeding window to a certain period of the day. You may have heard of the 16:8 fasting diet in which you fast for 16 out of the 24 hours of your day and then eat for the remaining 8. For example, using this method, your first meal of the day could be at 12 pm and then the last meal of the day is at 8 pm. There is a good chance you or someone you know may have tried a similar type of diet and lost weight. But why? The “science” behind intermittent fasting is quite simple – those with a shorter feeding window will 1) have limited time to eat and thus avoid additional meals / snacking 2) be generally less hungry between one meal to the next and thus, will probably eat less calories.
In the short term, there has been multiple studies that prove this method is effective for weight loss. However, it is important to note the root cause of this weight loss. Hint: it’s not actually meal timing. Participants in these studies were losing weight because they were in a calorie deficit, or eating less calories than it took to maintain their current weight. What does this mean for you? Well, for the general population, excluding those who are pregnant, have a history of eating disorders, or have a medical condition, it means that intermittent fasting could be a viable tool for weight loss if your calories throughout the day are also considered.
What if intermittent fasting is not realistic for your schedule but you are still looking for ways to manage your weight? Does meal timing matter at all if calories in/out are ultimately going to dictate your weight fate? Before we rule out timing all together, there are some things you should consider. Following your circadian rhythm, which are the physical, mental, and behavioral changes that follow a 24-hour cycle, may provide an advantage to weight management. Studies in young adults found that eating close to when levels of melatonin (sleep hormone) start to rise (i.e., close to bedtime), is associated with having more body fat.1 Therefore, it may be advised to get a majority of your calories during daylight hours. In fact, a randomized weight-loss study found that women with obesity who ate earlier in the day lost more weight. 1 Another randomized trial performed at Johns Hopkins found that healthy young adults burned less fat when they ate dinner at 10 p.m. compared with when they ate the same dinner at 6 p.m.2 This is partially because the body is more efficient at digesting and metabolizing food earlier in the day while you’re active, and less efficient late at night or early in the mornings.
What’s more is that eating a large meal late at night could cause sleeping problems as your body must work to digest our food instead of resting. This can delay your ability to fall asleep and could prevent you from getting quality, deep sleep. Insufficient sleep is associated with higher levels of the hormone ghrelin, which increases appetite, and lower levels of the hormone leptin, which leads us to feeling less full..3 Additionally, when you are sleep deprived, it is harder for you to make healthy choices and resist cravings because the lack of sleep dulls activity in the brain’s frontal lobe, the locus of decision-making and impulse control. 4
Putting it all together - although your overall calories will be the largest and most important component of weight management, meal timing should not be completely ignored. While there is no perfect time to eat your meals each day, there is evidence suggesting that avoiding large late meals and getting most of your calories earlier on could be beneficial to your health and steading the scale.
