Types of foods eaten are a crucial factor in weight loss and health, but the timing of meals may also have an impact, according to new research published recently in the journal Obesity.

The researchers from Tel Aviv University (TAU) in Israel found that those who eat their largest daily meal at breakfast are far more likely to lose weight and waist line circumference than those who eat a large dinner.

“Metabolism is impacted by the body’s circadian rhythm – the biological process that the body follows over a 24 hour cycle,” said lead researcher Professor Daniela Jakubowicz, of TAU’s Sackler Faculty of Medicine and the Diabetes Unit at Wolfson Medical Centre. “So the time of day we eat can have a big impact on the way our bodies process food,” she said.

The study found that participants who ate a larger breakfast – which included a dessert item such as a piece of chocolate cake or a cookie – also had significantly lower levels of insulin, glucose and triglycerides (fats in the bloodstream) throughout the day. According to the researchers, this translates into a “lower risk of cardiovascular disease, diabetes, hypertension, and high cholesterol”.

“Dramatic difference” between big breakfast and big dinner groups

To determine the impact of meal timing on weight loss and health, the researchers randomly assigned 93 obese women to one of two isocaloric groups. Each consumed a moderate-carbohydrate, moderate-fat diet, totaling 1,400 calories daily for a period of 12 weeks. The first group consumed 700 calories at breakfast, 500 at lunch, and 200 at dinner. The second group ate a 200 calorie breakfast, 500 calorie lunch and 700 calorie dinner. The 700 calorie breakfast and dinner included the same foods.

By the end of the study, participants in the “big breakfast” group had lost an average of 17.8 pounds each, and three inches off their waist line, compared to a 7.3 pound and 1.4 inch loss for participants in the “big dinner” group. According to the researchers, those in the big breakfast group were found to have “significantly lower” levels of the hunger-regulating hormone ghrelin, an indication that they were more satiated and had less desire for snacking later in the day than their counterparts in the big dinner group.

The researchers also found the big breakfast group showed a more significant decrease in insulin, glucose and triglyceride levels than those in the big dinner group. More importantly, researchers said this group did not experience the high spikes in blood glucose that typically occur after a meal. Peaks in blood sugar levels are considered even more harmful than sustained high blood glucose levels, leading to high blood pressure and greater strain on the heart.

Eliminating late-night snacking may help, researchers say

The researchers said the findings suggest that people should adopt a well thought out meal schedule, in addition to proper nutrition and exercise, to optimise weight loss and general health. The study also found that those in the big dinner group actually increased their levels of triglycerides, despite their weight loss.

The researchers suggested putting an end to late night snacking.

“Mindless eating in front of the computer or television, especially in the late evening hours, is a huge contributor to the obesity epidemic,” Professor Jakubowicz said.

The study was done in collaboration with Dr Julio Wainstein of TAU and the Wolfson Medical Centre, and Dr Maayan Barnea and Professor Oren Froy at the Hebrew University of Jerusalem.

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