We interrogated more than half a million days of food diaries to see whether it is actually helpful.
The chart below shows the proportion daily calories consumed at breakfast versus the proportion of a person’s daily target calories consumed based on their food diaries. A score of 100% would mean that they achieved their calorie goal. A score of less than 100% indicates the individual was able to consume less than their goal intake for the day.
The data from people eating three or more times a day indicates that, on average:
- people who ate the least for breakfast tended to eat more across the day, while
- people who consumed more of their daily calories at breakfast tended to eat less during the day.
People who front-loaded their calories at breakfast tended to eat around 20% less across the day!
Looking at the data for lunch, we see a similar trend.
If you can fit it into your lifestyle, a larger lunch seems to be better.
Where this data gets interesting is when we look at dinner.
People seem to do OK if their dinner is similar in size to breakfast and lunch. However, we tend to overeat if we consume the majority of our calories at night.
Putting it all together
When we overlay all three meals, we see that prioritising breakfast is a good idea if you want to get or stay lean.
If you are already lean and need to recover from a hard day of activity, then eating at night will help you consume more energy and store it more effectively.
But is this result due to behaviour or biology? Or perhaps a bit of both?
It’s possible to explain why we overeat at night from a purely behavioural perspective.
It can be hard to eat a lot at breakfast when you need to get off to work or at lunch when we might be at work or school and have to prepare a lunch and bring it from home.
But then at night, we have the fridge.
We have our friends and family.
We have Netflix.
We have the perfect storm of comfort food, social eating and self-soothing combined with being surrounded by less than optimal food choices that we tend to fill our patry and fridge with.
Food eaten later also has to be stored, at least until the next day to be used when we are more active.
Locking in your circadian rhythm
There have also been a number of interesting studies looking at the relationship between food timing and how it affects our body.
Compressing your feeding window to give your body a chance to spend time in a fasted state is useful. However, it seems shifting your eating window earlier in the day is also beneficial. This is commonly known as Early Time-Restricted Feeding (or eTRF).
Just like it’s beneficial to get sunlight in the morning and not gaze at blue light from our screens all night, it seems it’s also important to lock in our circadian rhythm with food in the morning and not overdo it at night.
While keeping body fat levels low is important for diabetes management, eating earlier seems to improve our insulin sensitivity independent of weight loss.
We have greater insulin sensitivity in the morning. Our body is primed to use food. Food eaten later in the day is more likely to be stored for longer.
How to do it
eTRF is not always the most convenient thing.
Lots of people are not hungry in the morning, particularly if they tend to eat a large evening meal.
Left to our own devices, we tend to optimise for maximum storage to prepare for the coming winter.
Most people find it takes a week or two to get into the new groove of eating earlier.
Eating your main meal with the family at night is more social and eating in front of the TV when you’re relaxing can be fun. But if you need that extra edge to manage your weight or diabetes then moving some of your dinner calories to breakfast might just be worth the effort.