Christian, there was a study that recently came out that showed regardless of how many calories you are at breakfast, your body burned more of them up during digestion and less at night. So it does appear that eating a big breakfast helps from the standpoint that more of those calories will be burned for energy and less stored as fat…
This is a nutrition study that did the rounds back in February, generating headlines like:
“A big breakfast may help you burn double the calories”
“Eating a big breakfast burns twice as many calories as a big dinner, study finds”
“People who eat a big breakfast burn twice as many calories compared with those who eat a larger dinner”
When I looked at the study for myself (as opposed to simply copying and pasting the press release), it does show that diet-induced thermogenesis – the energy cost of digesting and processing the food you eat – was around 2.5 times higher when a meal was eaten in the morning compared to that same meal consumed in the evening.
Which sounds like it matters, but only until you dig deeper into the results.
On average, diet-induced thermogenesis was around 0.7 kilojoules per minute when a meal was consumed in the morning. When that same meal was consumed in the evening, diet-induced thermogenesis came to roughly 0.3 kilojoules per minute.
You can see this for yourself in the figure below, which shows the average diet-induced thermogenesis (including all time points of measurement as well as high- and low-calorie meals) after breakfast versus dinner.
After crunching the numbers over the 3.5-hour post-meal measurement period, the difference between a meal consumed in the morning and one consumed in the evening was roughly 84 kilojoules.
That is… drum roll… a total of 20 calories.
In other words, eating a big breakfast burned an extra 20 calories compared to the same meal consumed at dinner.
Given that a pound of fat contains around 3500 calories, it’s going to take a very long time before those extra 20 calories manifest themselves as an increase in the rate at which fat is lost.
Remember, this study didn’t measure long-term changes in fat loss. You only need to look at the research on fasted cardio to see why short-term changes in fat metabolism don’t always translate into long-term effects on fat loss.
Losing fat and keeping it off is more about building habits and routines that work for you than it is about basing what and when you eat on small differences in diet-induced thermogenesis.
If you find it easier to stay within your calorie budget for the day with a big breakfast and a small dinner, go for it.
But if breakfast isn’t your thing, or you don’t get peckish until the afternoon, there’s nothing wrong with starting the day with a cup of coffee and little else.
As long as a few nutrition boxes are being ticked, the way you distribute your calories over the course of the day is down to personal preference, and won’t have a great deal of impact on your results one way or the other.
Christian Finn is the nation’s leading authority on science-based, joint-friendly ways to build muscle. A former “trainer to the trainers,” he holds a masters degree in exercise science, and has been featured in or contributed to major media on two continents, including the BBC and Sunday Times in the U.K. and Men’s Health and Men’s Fitness in the U.S.