Weight Gain – It Matters when You Eat
Have you ever wondered what sumo wrestlers do to gain so much weight? They eat a lot, of course. But in order to really gain weight, they save their largest and heartiest meals for the evening. This is just an anecdote but there is enough evidence to show that it is not just what we eat but also when we eat that determines our weight gain.
And yet, have you ever wondered why, despite fasting the whole night, most of us are not terribly hungry in the morning? Not only that we are not starving, many people quite happily skip breakfast. But not too many of us would think of skipping dinner. Statistics show that for most people breakfast is the smallest meal of the day. In countries of Western culture, breakfast makes up a mere 16-18% of our daily calorie intake, in comparison with dinner, the largest meal of the day, accounting for approximately 35%.
The internal circadian rhythm regulates our metabolic response to food and the body deals with food more efficiently earlier in the day, rather than later, whereas late night eating can promote cardio-metabolic risk factors for heart disease and diabetes. But latest evidence shows that the circadian rhythm also plays a key role in determining appetite and hunger. Typically, hunger and appetite are diminished in the morning and hit their peak in the evening, encouraging us to consume larger meals in order to get ready for the overnight fast. We are practically programmed to want to skip breakfast in favour of consuming large evening meals.
A recent research published in the journal Obesity that was based on a small, but rigorous study of twelve healthy non-obese adults, confined to a laboratory setting for thirteen days, in very dim light with scheduled meals and sleep confirms this observation. This highly regulated setting allowed examining the true effects of the internal circadian rhythm on hunger and appetite. It revealed that participants felt least hungry around 8am in the morning and most hungry around 8pm in the evening.
In fact, this urge to eat more food in the evening would have provided a survival advantage for our ancestors, enabling them to more efficiently store away energy in order to better overcome periods of food scarcity. When we translate this to the 21st century setting, with its abundance of high energy foods, sedentary lifestyles and artificial lighting that extends the reaches of our ‘day’ late into the evening, it is easy to understand the negative implications of late night snacking. The intensified drive to eat energy rich foods in the evening appears to be a potential driving force promoting obesity.
Of course, weight gain and the modern-day obesity epidemic are not solely due to the timing of when we eat. Eating too much and eating a bad diet while not exercising will promote obesity too. However, it looks increasingly likely that it is not just what we eat but also when we eat that matters when it comes to our waistline. If you wish to keep weight gain at bay, eating your larger meals earlier in the day and lighter meals in the evening sounds like a good strategy. But really, how many times have you heard the old wisdom that says: breakfast like a king, lunch like a prince and dine like a pauper?
Where to Find Related Information: National Sleep Foundation