Eating a big breakfast and a light dinner doesn’t make you burn more calories, a study found

The popular notion that a hearty breakfast and light dinner helps people burn more calories may be wrong.

A new study published Friday in the journal Cell Metabolism found that eating the majority of your calories in the morning doesn’t help people lose weight any more than eating those calories in the evening.

The results were based on a controlled experiment involving 30 adults in the UK who were obese or overweight. For four weeks, the participants followed one of two diets: about half of them ate 45% of their daily calories at breakfast, followed by 35% at lunch and 20% at dinner. The other half consumed 20% of their daily calories at breakfast, followed by 35% at lunch and 45% at dinner.

The groups then swapped places and followed the opposite regime for another four weeks.

Both groups consumed just over 1,700 calories per day. The full breakfast consisted of foods such as cereal, toast, eggs, sausage, smoothies, and yogurt. Big dinners consisted of dishes like beef and mushroom stroganoff with rice, pasta bolognese, or pork chops with potatoes and peas.

Researchers don’t often provide study participants with meals, so the study offers a rare look at how one factor — the timing of a person’s largest daily meal — affects metabolism and weight loss.

In the end, the researchers added up how much total weight each group lost after four weeks of the big breakfast diet and the big supper diet. The result was the same: around 7 pounds.

According to Courtney Peterson, an associate professor of nutrition at the University of Alabama at Birmingham who was not involved in the research, this is clear evidence that eating a full breakfast doesn’t burn more calories.

The results show that “there’s no magical fat-burning effect in timing your meals,” Peterson said.

However, participants in the study said they felt less hungry throughout the day when they got the majority of their calories at breakfast. So it’s possible that a full breakfast could help with weight loss over longer periods of time by reducing appetite, Peterson said.

“There are two ways to lose weight: either you burn more calories or you eat less,” she says. “In the real world, when people are less hungry, they eat less hungry, which usually translates into weight loss.”

Alexandra Johnstone, the study’s lead author and researcher at the University of Aberdeen in Scotland, said a big breakfast may also “help people control appetite to stick to a high-calorie diet.”

Early meals could still have benefits

In contrast to the British study, other research has shown that people who eat a large breakfast can see a decrease in their body mass index.

Martha Belury, a professor of human nutrition at Ohio State University, said the new study might have found a greater weight-loss effect if the researchers had given subjects higher-quality, nutrient-dense foods.

“Certain foods, if you have a lot of them or a little bit of them, can stimulate more hunger than other types of foods,” she said.

But weight loss aside, there may be other good reasons to eat a big breakfast. Johnstone said people are more insulin sensitive in the morning, so an early meal might help regulate blood sugar levels. On the other hand, eating late — after around 8 p.m. — could raise blood sugar levels and cause people to store more energy as fat.

Johnstone’s study found no improvement in blood sugar levels from a heavy breakfast. But a study of overweight or obese women in Israel showed improved blood sugar levels in those who ate a 700-calorie breakfast, followed by a 500-calorie lunch and a 200-calorie dinner.

The new research also has implications for intermittent fasting, an eating plan in which food intake is limited to a specific window — typically eight hours a day.

“What this study suggests is that for people with time-restricted food intake, it may be better to limit time in the evening and eat between the morning and afternoon hours,” Johnstone said.

That’s likely because people who fast in the morning are hungrier in the afternoon and evening and take in more calories than those who start eating earlier, Peterson said.

As with the big breakfast strategy, the relationship between intermittent fasting and weight loss is complicated.

“About half of the studies find a weight loss effect and half don’t,” Peterson said. “To me, that suggests there’s probably a benefit there, but we need to go to even larger studies to demonstrate that.”

Belury said a person’s eating routine should take into account the times of day when they burn most energy and their individual response to food.

“There’s quite a lot of personal preference in terms of eating habits in general,” she said. “Some people, for whatever reason, say they don’t like a big breakfast because they think if they have a big breakfast, they still have a big lunch.”