The new statement from the American Heart Association (AHA) provides an overview of current scientific evidence suggesting that when and how often individuals eat may affect their risk factors for heart attack and stroke, as well as other cardiac and blood vessel conditions.
Research has shown that adult behavioral patterns of eating meals and snacks have changed over the past 40 years in the United States.
For women, there has been a reduction in energy intake from meals, from 82 percent to 77 percent, and an increase in energy intake from snacks, from 18 percent to 23 percent. Similar trends have been reported in men.
The tendency to eat three standard meals per day has also declined in both men and women. People in the U.S. now have a habit of eating around the clock rather than sticking to certain meal times.
"Meal timing may affect health due to its impact on the body's internal clock," says Marie-Pierre St-Onge, Ph.D., writing group chair, and an associate professor of nutritional medicine at Columbia University in New York City.
"In animal studies, it appears that when animals receive food while in an inactive phase, such as when they are sleeping, their internal clocks are reset in a way that can alter nutrient metabolism, resulting in greater weight gain, insulin resistance, and inflammation," St-Onge explains. "However, more research would need to be done in humans before that can be stated as a fact," she adds.
Daily breakfast consumption may help prevent chronic disease
Breakfast is often described as the "most important meal of the day," yet research indicates that 20-30 percent of U.S. adults skip breakfast. The decline in breakfast consumption has been associated with an increase in obesity rates. Furthermore, skipping breakfast has been connected with a greater risk of cardiovascular disease, type 2 diabetes, and chronic disease.
The AHA researchers suggest that if U.S. adults were to eat breakfast every day, the adverse effects associated with glucose and insulin metabolism would be reduced. They also suggest that comprehensive dietary advice that supports daily breakfast consumption may help people to maintain healthy dietary habits throughout the day.
Meal timing and frequency have been linked to heart disease and stroke risk factors, which include high blood pressure, cholesterol, and blood glucose levels, as well as obesity, insulin resistance, and insulin sensitivity.
Focusing on meal timing and frequency may be a starting point for addressing the obesity epidemic. Making dietary changes that promote regular energy intake with a majority of calories consumed earlier in the day has been shown to have positive effects on risk factors for heart disease, diabetes, and body weight.
Moreover, guidelines that revolve around meal frequency and timing may help people to improve the quality of their diet without having to restrict calories to promote weight loss.
Larger studies needed to confirm how meal timing impacts disease risk
The statement notes that while the research shows that there is a relationship between meal habits and cardiovascular health, there is currently not enough evidence to show that certain eating patterns cause better and lasting benefits.
Further long-term studies of meal habits are needed before conclusions can be reached on the impact of meal frequency on heart disease and diabetes.
"We suggest eating mindfully, by paying attention to planning both what you eat and when you eat meals and snacks, to combat emotional eating. Many people find that emotions can trigger eating episodes when they are not hungry, which often leads to eating too many calories from foods that have low nutritional value."
Marie-Pierre St-Onge, Ph.D.
St-Onge and colleagues also say that there is a link between occasional fasting - that is, 1-2 times per week or every other day - and short-term weight loss.
"All activities have a place in a busy schedule, including healthy eating and being physically active," says St-Onge. "Those activities should be planned ahead of time and adequate time should be devoted to them," she concludes.
Meal timing and frequency: Implications for cardiovascular disease prevention, Marie-Pierre St-Onge et al., Circulation, doi:10.1161/CIR.0000000000000476, published online 30 January 2017.
AHA news release, accessed 30 January 2017 via AlphaGalileo.