Unhealthy weight gain is a problem that many Americans have to tackle and which state-led programs promoting wholesome dietary habits seek to prevent. According to the Centers for Disease Control and Prevention (CDC), 36.5 percent of adults, and around 17 percent of children in the United States live with obesity.

Excess weight also puts people at an increased risk of developing serious conditions or diseases, including heart disease, type 2 diabetes, and some types of cancer.

Research into nutrition, healthy eating habits, and how our diet impacts our day-to-day lives is conducted on a regular basis, with new discoveries being reported all the time. For instance, an analysis recently covered by Medical News Today suggests that some biomarkers could predict the effectiveness of weight loss diets.

A new study on the link between the impact of meals and their frequency to weight gain has now been conducted by Dr. Hana Kahleova, from the Loma Linda University School of Public Health (LLUSPH), in California. She collaborated with colleagues from her own institution, as well as from the Institute for Clinical and Experimental Medicine and the Institute of Endocrinology, both based in Prague, Czech Republic.

Their results were published in The Journal of Nutrition, and they were co-written by Prof. Gary Fraser, from LLUSPH. Dr. Kahleova will present the findings at the International Conference on Nutrition in Medicine, in Washington, D.C., on July 29.

Participants with peculiar eating habits

Researchers worked with participants from the Adventist Health Study-2 (AHS-2), an endeavor monitoring the health lives of 96,000 Seventh-day Adventists from the U.S. and Canada.

The AHS-2 considers that the Adventist population is situated at a lower risk of developing conditions and diseases such as hypertension, heart disease, cancer, or diabetes. This, researchers suggest, may be thanks to their specific eating habits.

Led by Dr. Kahleova, the study included 50,660 adult individuals from this population, all aged 30 or older. The focus was on the possible link between when and how often people eat, and their body mass index (BMI).

The participants had various body types and sizes, the researchers specify, and their eating habits and health outcomes were monitored for an average period of 7 years.

At the outset, the participants were asked to fill in a questionnaire, detailing their medical history, eating practices, physical activity, and other relevant information. As the study went on, they filled in follow-up forms declaring any major health events. The final follow-up questionnaire reported how often participants had normally taken their meals, and at what times of the day.

Breakfast is good, dinner less so

The study had several main findings. In the first place, it showed that people who regularly ate only one or two meals per day had a decrease in BMI. Conversely, those who ate more than three meals a day increased their BMI, and the more meals they ate, including snacks, the greater the weight gain.

The researchers also found that people who had breakfast regularly tended to lose more weight than people who chose to skip breakfast.

More importantly, the participants whose largest meal of the day was breakfast experienced a large BMI decrease, in contrast with those who made lunch or dinner their largest meal.

Additionally, the researchers found that skipping dinner altogether and having a long, 18 or 19-hour, overnight fast contributed to weight loss.

Other good eating practices, the researchers observe, include leaving 5 or 6 hours between breakfast and lunch, and abstaining from snacks throughout the day.

These findings confirm what previous studies conducted on smaller population samples also inferred. The importance of breakfast to our diet and its impact on our general health have long been appreciated, yet this is the first recent analysis to be conducted on such a large, unrestricted population sample.

Age affects BMI

The researchers also highlighted that there is a strong link between BMI and advancing age. According to them, participants younger than 60 tended to gain more weight, whereas those over 60 tended to experience a loss in BMI.

In this context, they note that people under 60 with more mindful dietary habits, who eat breakfast as their main meal, tend to avoid the weight gain that is to be expected in their age category.

"Before age 60 years, those eating calories earlier in the day had less weight gain," says Prof. Fraser. "Over decades, the total effect [of regularly eating a large breakfast] would be very important," he adds.

At the same time, the study observes that people over 60, who naturally lose more weight, will be similarly affected by this regime, which could lead to negative health outcomes in some cases.

A clearer understanding of the impact that meal frequency and the importance that meals have on BMI levels could, therefore, help us make better, more informed decisions about our individual health and dietary needs.