If I ask you what comes to mind when you think about eating better for weight loss, would it be adding in extra servings of fruit and vegetables to your meals? Reducing sugar and processed carbs? Looking at your calorie intake?
Whilst these are all valid points, one factor which is often overlooked is not just what kind of nutrition you fuel your body with but also when you fuel your body.
Our bodies run on a 24-hour clock - a bio-circadian rhythm. For instance, your heart rate and blood pressure naturally rise in the afternoon and are lowest while you sleep. This rhythm helps us be alert when we wake up, it has our digestive system ready to process food when we eat, and it helps our organs rest and repair while we sleep. Our biology is a clockwork of chemical and hormonal rhythms whose timing is critical for our survival and well-being.
When it comes to weight gain, fatigue, overeating, digestive upset to name just a few, it is important to not only look at your nutritional intake but also look at the times at which we eat.
One of the simplest ways to measure the metabolic rate (needed for calorie burning) of the human body is to take its temperature. Essentially, the warmer you are, the more metabolic you’ll be and ultimately, the better you will digest, assimilate, and burn calories.
Body temperature has a rhythm that is similar for most of us, and this daily shift in body temperature can allow us to maximise our metabolic potential and in turn calorie burn. Here’s how our body temperature changes. During the night time and early morning hours when we sleep, our body temperature drops. Our body is in a state of rest, healing, and repair.
As soon as you wake in the morning, your body temperature automatically starts to increase.
Your metabolism wakes up when you wake up. Since you’re naturally warming up in the morning, eating at this time is a good idea if you’re trying to lose weight. Eating quality food in the morning can increase the metabolic rate and provide your body with the nutrients its preparing to process. Think of your metabolism as a fire. When you add fuel, the heat increases. The better and more regular the fuel quality, the more efficiently the fire (ie metabolism) will burn. Combine that good morning meal with good quality oxygen ie quality breathing, and you have yourself the ultimate metabolic calorie burning machine.
Interestingly, those that eat breakfast tend to not only burn more effectively, but also tend to eat more regular meals throughout the day (ie less binging) and begin and end their eating earlier in the day, with often reduced sugar cravings in the afternoon. For many people who skip breakfast, it can lead to eating later on in the day, eating larger meals, and snacking throughout the day and especially at night - resulting in an increase in overall calorie intake across the day compared to those that do eat breakfast.
Ok, back to body temperature. As the morning progresses, our body temperature continues to rise and peaks around midday. We therefore have our best digestion and metabolic function at lunchtime. Consequently, it makes biological sense to eat our largest meal at midday, when our ability to digest food is at its strongest.
In the afternoon, our body temperature dips which is what is often referred to as the afternoon slump and is generally the time that people start reaching for the caffeine and sugar to try to reverse that drop in energy and increase in tiredness. However, it’s normal to have this - this is when blood energy is being rerouted to digestion after our midday meal.
In the late afternoon/early evening your body temperature starts to rise again. You may notice your energy returning. However, by around 9pm, it starts it's downward descent as it gets ready for sleep. Sleep research has indicated that we cannot fall asleep unless body temperature is dropping. More often than not though, we have it round the wrong way. We tend to do a small to non-existent breakfast, a moderate sized lunch, and a big dinner and late night snacking before bed. End result can be increased body temperature and in turn, disrupted sleep and weight gain.
In our busy and over-stimulating world, our circadian rhythm could use some help.
The two biggest cues you can give your body to tell it the time of day are light and food. Biologically, we are designed to wake with the sun and go to sleep with the moon. Evolutionarily, those were very reliable cues to know the time of day. But in modern society, light and food are available around the clock which can lead to rhythm disruption.
When you eat can be as important as what you eat.
Research has been undertaken to investigate the timing of meals and impact on weight, in which one group of people were put on a 2,000 calorie diet but could only eat their 2,000 calories at breakfast, with nothing more for the rest of the day. With this one meal in the morning, everyone either lost weight or maintained their existing weight. In the second group of the study, the same exact people ate the exact same 2,000 calories diet, except this time, they could only eat it at dinner. With this one meal for the entire day, eaten in the evening, every single person in the study gained weight. Can you see why counting calories to lose weight can be a waste of energy if we don’t take into account when we eat those calories?
We burn calories more effectively in the first half of the day and much less efficiently in the late evening hours, so, if you want to get the ultimate metabolic benefit of eating, don’t eat your largest and most nutrient-dense meal when your digestion is slowing down in the late evening. Don't skip breakfast. Eating minimal food during the day and a lot in the evening will never take you where you want to go when it comes to optimising energy and burning calories. If weight loss is eluding you, why not think about how you can reset your metabolic rhythm to eat a good breakfast, a main meal at lunch time and a light dinner at night and notice what impact this has to overall shape shifting and ultimately weight loss.