The evidence is not clear on how – or even whether – snacking, breakfast eating or meal size links to weight. A large study adds new data to this body of research suggesting that fewer daily meals and snacks can help prevent weight gain, at least for this healthy group. For cancer prevention, staying a healthy weight is key to reducing risk for many common cancers like endometrial, postmenopausal breast and colorectal.
The authors analyzed data from the Adventist Health Study that includes over 50,000 North American adults. At the beginning of the study, participants reported their height and weight, as well as health habits like exercise, sleep and television watching. They also reported their eating habits via 24 hour recalls and a food frequency questionnaire.
The participants – members of the Seventh Day Adventist Church – tend to be more health-conscious, nonsmokers, mostly nondrinkers and eat less meat than most Americans.
Researchers used this data to determine how many meals – including snacks and breakfast – participants ate, and which meals were typically largest. They calculated participants’ weight changes by comparing Body Mass Index (BMI) at the beginning and end of the study.
An average of 7 years later, the study found:
- For participants eating 1 or 2 meals a day, their BMI decreased in comparison to those eating 3 meals per day.
- Having a larger breakfast or lunch, with a smaller dinner, linked to lower BMI when compared to those eating large dinners. And going longer between dinner and the next day’s breakfast was associated with lower weight.
- The more meals and snacks participants ate per day, the more their BMI increased compared to those who ate less often.
While the study can’t say why this would happen, one reason could simply be that it’s easier to eat more food – and therefore more calories – than you need with each eating occasion.
This is an observational study so it can’t establish cause and effect, but it does suggest that eating a large breakfast and lunch, with a smaller evening meal may be one strategy to help adults maintain a healthy weight over time – and possibly support healthy weight loss.
Research on eating timing and amounts is challenging to do in diverse populations and there are a lot of conflicting study results on the topic. For years, breakfast was considered an important tool for weight loss, but a major study last year found that it didn’t matter. Other research suggests that eating more often throughout the day can help with weight loss. But there are also lots of studies on the potential benefits of intermittent fasting, long periods of not eating that can span from 18 hours to a few days.
This is a nice summary and practical take on what we know from the research now.
There are many ways to work toward weight loss – or maintenance – that is both healthy and follows a cancer preventive diet. If you’d like to make changes with some specific goals and help from AICR dietitians, sign up for our free, online 12-week healthy habits, healthy weight program The New American Plate Challenge, starting in September.
The study was funded by the National Cancer Institute, the World Cancer Research Fund (AICR’s global partner), and the Ministry of Health, Czech Republic.