Can skipping dinner cause you to gain weight? It seems counterintuitive, but researchers in Japan say that seems to be the case.
Previous studies have determined a link between skipping breakfast and being overweight. Last year, for example, researchers in China published the results of a large systematic review and meta-analysis (analysis of data from several clinical trials) of observational studies and found that skipping breakfast is associated with and increases the risk of overweight and obesity and there was little difference among “ages, gender, regions, and economic conditions.” But few researchers have considered the effect of skipping dinner on weight.
Over an average period of three years, the researchers followed more than 25,000 students over the age of 18 at Osaka University in Japan. About two out of three were men. The students, as part of the annual physical exams the university provides its undergraduate and graduate students, were asked how often they ate breakfast, lunch and dinner. The researchers also factored in other variables, such as what time they ate, whether their meal habits changed during the study period, whether they smoked or drank, and what their weekday sleeping patterns were.
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Not many students skipped dinner “often” (only 20 men and 32 women) and even fewer skipped dinner “usually” (four men and 11 women). For that reason, the researchers divided dinner frequency into two groups — those who ate dinner every day and those who skipped it more or less “occasionally.” The researchers found that those who did skip dinner tended to be older and sleep less and were more likely to smoke or drink, to eat dinner later, and also to skip other meals.
The effects of skipping dinner
After adjusting for other factors, the researchers reported that male students who skipped dinner more or less occasionally were at a higher risk of a 10% or greater weight gain than those who ate dinner, while those who skipped breakfast were not. Among the female students, the researchers found that the incidence of a weight gain of ten pounds or more was “significantly higher” in the female students skipping dinner more or less occasionally than in those eating every day. However, no significant difference was observed in how often the students ate breakfast and lunch. As the researchers expressed their findings, “skipping dinner was significantly associated with ≥10% weight gain and overweight/obesity (BMI ≥ 25 kg/m2) in both male and female students. These results suggest that skipping dinner, which was much less prevalent than skipping breakfast, has a stronger association with weight gain and overweight/obesity than skipping breakfast.”
Why skipping dinner may lead to weight gain
The question, of course, is why? One possible cause, the researchers speculated, was that skipping dinner ultimately makes people hungrier so that they eat more during the rest of the day. Another factor might be related to “low diet quality.” The researchers pointed out that “skipping dinner significantly reduced intake of vegetables and seafood/plant proteins compared with skipping breakfast. Because a recent systematic review clarified that low vegetable intake and fish intake were associated with weight gain, the greater impact of skipping dinner on weight gain may be due to the larger decrease in vegetable and seafood/plant protein intake.”
Finally, the researchers surmised that the weight gain might have to do with whether the individual was a “morning person” or an “evening person” (that is, whether they were more alert in the morning or evening). They noted that an earlier study in Japan reported that women students who went to bed late and got up late (“night owls”) were more likely to gain weight. This same study also found that the night owls were more likely to skip dinner.