Do large breakfasts really help weight loss?

“Breakfast like a king, lunch like a prince and dine like a pauper!” has for as long as I can remember been the dietary dogma for people wanting to remain a healthy weight. The argument was that front-loading your calorie intake across the day like this benefits metabolism and makes you less likely to pile on the pounds. But is this actually true? Well, it turns out that, in metabolic terms at least, it’s wrong. Nevertheless, it might still be a valuable aid to weight control, because while this dining pattern won’t affect how many calories you burn, it might affect how much you eat in the first place. James Tytko got his teeth into the subtleties of the science with Aberdeen University’s Alexandra Johnstone…

Alexandra - Breakfast like a King, dine like a pauper is quite old fashioned. We know that what we eat influences our health, but what this study that we've published recently looks at is does, when we eat specifically impact on weight loss? Does timing of eating influence the ability for the body to mobilize and use those calories so that we can get the maximum amount of weight loss? So we have quite a specialized facility at that I worked and that we can prepare all the diets individually for our volunteers. And that really helps us achieve this type of very controlled studies where we can look at mechanistic nutrition. We had a big breakfast and a small dinner menu, and we had a small breakfast and a big dinner menu. So each subject acts as their own control. So what we're sensibly doing is comparing subjects on each of their diets. So we're not comparing subjects between each other. So within subject design. And that's really important because we are interested in appetite and appetite as a subjective sensation. What we found was that weight loss was almost identical over the four week period of each diet. And that suggests to us that actually time of day is not relevant in terms of energy metabolism.

James - Can you tell me a bit more about your subjects? Were they people who were aiming to lose weight?

Alexandra - In the study? We use an opt in approach. So yes, these are people who were extensively overweight or obese, but healthy. So it's people who are interested in taking part in our diet studies and have a commitment and time to only eat the food that we provide over a nine week period.

James - So you mentioned that on both diets, there was no change overall in their weight loss or gain. Does that mean we can consign this idea of front loading calories early in the day to old wives tale status? Is a diet that promotes eating at certain times of the day, unlikely to be effective?

Alexandra - So that's an interesting question, isn't it? Does time of day have any influence on appetite or energy balance? And actually what we found is that it does. So our main finding is that it didn't influence weight loss in terms of energy metabolism and energy expenditure, but we did find something interesting. And that was that the big breakfast regime had an impact on appetite, such that subjects reported feeling more full and less hungry when they were eating a big breakfast compared to a small breakfast. Now I think this could be really useful in what I call the real world. So it's extrapolating out our results for those people who are looking for strategies to help them lose weight. Then this could be beneficial and this will be an area for future research for us. One of the reasons that people fail to comply with a weight-loss diet is because they feel hungry. So if you start the day with our bigger breakfast, then that can potentially have an impact on behavior, because remember feeding is a form of behavior. And if you can stick to the calorie deficit over a period of time, then that type of regime could be helpful.