Is one better than the other, or are they the same?
You’ve heard it a thousand times: Eating six small meals per day is better than eating three big ones. In the interest of obesity prevention, a wealth of research has aimed to determine whether or not snacking can influence body weight or energy intake better than eating traditional meals can. The widely accepted Booth Hypothesis implies that the growing trend of “grazing,” instead of consuming the traditional three “proper” meals plus beverages and snacks between them, is a major factor in the prevalence of obesity in the U.S. If this hypothesis is true, it must be assumed that extra snacks increase the total number of calories consumed, ultimately causing weight gain (Speechly & Buffenstein 1999).
Research on this issue is “messy.” Some studies have supported one approach; other studies have supported the other. To compare these two eating strategies, a brief review of the nature of hunger and satiety should be considered.
Admittedly, much of the eating that people do is due to social or emotional triggers. True hunger is a series of physical sensations that catch the body’s attention so it can get the fuel that it needs. “When you’re hungry, you seek food,” says Barbara Rolls, PhD, author of the top-rated weight management book Volumetrics (Rolls & Barnett 2000).
Stomach growling and stomachache are two frequently reported physical sensations indicating true hunger. According to the Monell Chemical Senses Center in Philadelphia, lightheadedness, weakness, pain, dizziness, anxiety, loss of concentration, food cravings, mouthwatering and chronic thoughts of food have also been associated with true hunger (Rolls & Barnett 2000). Furthermore, eating increases the body’s blood sugar level so the body produces insulin to allow glucose to exit the bloodstream and enter cells desperate for energy; this physiological phenomenon is normal.
Typically, another physical sensation should occur at some point while one eats: satiety. Satiety is a feeling of fullness or satisfaction with the amount of food eaten and is often described as comforting or calming. It should be associated with the cessation of eating.
Unfortunately, many people are out of touch with the feeling of satiety. Marion Nestle—researcher, author and professor of nutrition at New York University—says, “You can’t teach satiety. People have to learn it themselves.” The bottom line is that recognition of both hunger and satiety is key to appropriate eating.
The quest to determine whether or not grazing is a better strategy than eating the traditional three meals began 40 years ago. Fabry and colleagues studied 379 men ages 60 to 64 to see whether or not there was a difference in body fat between eating three meals per day and eating five meals per day; they observed that men who ate three meals per day had larger skin folds than did men who ate five or more meals per day (Fabry et al. 1964). Metzner and colleagues also studied the relationship between eating frequency and body fat proportion in adult men and women; similarly, subjects who ate six meals per day were significantly thinner than those who ate two meals per day (Metzner et al. 1977).
These early studies began what appears to be an ongoing quest for a simple answer to a complex question. All in all, eating more frequently has been associated with reduced body fat and improved appetite control, weight control, lipid metabolism and insulin sensitivity (Drummond et al. 1998).
I interviewed Dr. Rolls about her recommendations for meal frequency based on her years of research as an expert on hunger and weight regulation.
Kristine Clark: Why would eating six small meals per day help people manage their appetite and lose weight better than eating a standard breakfast, lunch and dinner?
Barbara Rolls: Since weight loss is merely a function of energy in versus energy out, the truth lies somewhere between the two. As long as people hold their calorie intake constant—as long as they eat less than what they normally eat, whether in six or three increments —they will lose weight, regardless of the frequency.
Clark: Many studies appear to support the theory that spreading calories throughout the day is a better approach to appetite management.
Rolls: Only if the person eating makes the correct food choices. Theoretically, eating several small meals a day instead of one or two big ones helps stabilize the way the body burns fuel by avoiding the big calorie boosts that the body easily turns into body fat. However, smaller, more frequent meals have not been conclusively shown to help people burn calories more efficiently or lose more weight. In fact, in one recent study, the male subjects lost weight on frequent meals, but the women studied did not (Rolls, Morris & Roe 2002). This demonstrates the inconsistency in making that recommendation.
Clark: Should meal frequency simply be a matter of individual preference?
Rolls: Absolutely! Patterns of eating vary for all of us. No one pattern has been shown to work for everyone. For many people, eating more frequently means more snacks that could actually be higher in calories than planned, well- balanced meals eaten three times daily. In addition, the research demonstrating that five or more meals per day are more beneficial has been conducted in controlled environments. People who have easy access to food and constantly must decide whether or not to eat may not be able to determine whether or not the “snacks” they eat are the correct portions or are low enough in calories.
Clark: In your book Volumetrics, you suggest eating snacks that have 100 calories. Why this amount?
Rolls: Giving a definite number—quantifying the snack—guides people toward appropriate types of foods, such as lower-calorie fruits and vegetables and low-fat dairy products, such as string cheese or yogurt. That calorie amount also indicates a food’s ideal quantity or portion size.