Eating well used to be as easy as counting from 1 to 3: Until recently, most families followed the traditional pattern of eating three square meals a day. But now, more and more harried adults and children are opting for a much more irregular pattern of meal and snack consumption. Some of that irregularity can certainly be attributed to our hectic lifestyles. The easy availability of fast food has allowed people to find and consume a quick meal in almost any venue throughout the day.
But a growing number of people are actually choosing to eat more frequent meals for health reasons, not just for convenience. Some have made this lifestyle change in order to speed up their metabolism and thereby lose weight. But is this practice effective? And is upping meal frequency the best approach for achieving and maintaining a healthy weight? This article will look at the research behind meal frequency and weight loss and will recommend a healthy approach that you and your clients can use to balance energy intake on a daily basis.
Nibbling Away at the Science
The theory behind eating more meals each day is really not new. As far back as 1964, researchers first suggested that being overweight was inversely related to the number of meals consumed daily (Bellisle, McDevitt & Prentice 1997). Scientists observed that study participants who followed a pattern of “nibbling” each day had lower body weights than those with a pattern of “gorging” (Bellisle, McDevitt & Prentice 1997).
Further observational and interventional studies popularized this notion after finding that frequent eating patterns were associated with lower body fatness in schoolchildren and middle-age men (Bellisle, McDevitt & Prentice 1997). When body mass index (BMI) was examined in relation to meal frequency, a similar trend was found: Subjects with the lowest BMIs typically consumed more meals during the day than those who ate less often (Bellisle, McDevitt & Prentice 1997).
Problems With Study Underreporting
One potential flaw in some of the studies on meal frequency is that few subjects ever properly report the number of calories they eat each day. This dietary phenomenon of underreporting caloric intake can make the task of interpreting research results confusing, since most early studies on the topic of meal frequency depended on self-reported food intake data. The number of snacking “episodes” is especially suspect in some studies, since study participants often forget to report eating these little meals.
Fortunately, the development of more exact techniques for determining how much food participants consume has increased the accuracy of more recent studies. Researchers have come to expect that the average study participant will underreport daily food intake by about 20%, and that the margin can be as high as 50% for overweight and obese subjects (Bellisle 2004).
Meal Frequency, Metabolism & Energy Balance
Some researchers have suggested that eating small meals more frequently over the course of a day may provide a metabolic advantage for weight loss. In one study of people who were dieting, those who consumed seven meals each day had greater success with weight loss than those who stuck to three meals per day; while it was expected that energy restrictions would lead to some weight loss, those who ate more meals had more successful outcomes than the other dieters (Bellisle, McDevitt & Prentice 1997). However, other studies could not replicate these same findings in terms of meal frequency. In fact, most research suggests that greater meal frequency does not affect weight loss or provide a metabolic advantage while dieting (Bellisle, McDevitt & Prentice 1997).
So, what is the link between metabolism and weight loss? Weight maintenance is really a matter of energy balance: Energy balance is achieved when energy in is equivalent to energy out.
Energy in represents the amount of food you consume each day, whereas energy out is the number of calories you expend each day. When it comes to energy in, we know this much: Eating fewer calories than you expend results in weight loss, whereas eating more than you expend results in weight gain (Jéquier & Tappy 1999).
The Thermal Effect of Food
The energy out side of the equation is not as clear-cut as the energy in aspect. Energy out, also referred to as metabolic rate or total energy expenditure (TEE), is itself composed of three factors, as follows:
- resting metabolic rate (RMR) = the number of calories the body needs to maintain body functions while at rest
- thermic effect of physical activity (TEPA) = the number of calories expended during exercise
- thermic effect of food (TEF) = the number of calories needed to initiate nutrient breakdown and storage
RMR provides the largest component (about 60%–75%) of total daily caloric needs, while TEPA contributes 10%–40% (Poehlman & Melby 1998). TEF is the smallest contributor to total daily caloric need, at about 10% (Tappy 1996). We know that RMR and TEPA vary widely among individuals and that both can influence weight loss or gain. But what about TEF?
Each time food is consumed, TEF stimulates the body’s metabolic processes and calories are burned. It would seem logical that consuming small, frequent meals throughout the day would generate a higher TEF and thus a larger contribution to TEE. But does the research back up this assumption?
Unfortunately, the research on the metabolic effects of consuming a large meal versus many small meals is mixed. One study did find a significantly higher TEF in individuals who ate one large meal consisting of 750 calories versus those who ate six smaller 125-calorie meals (Tai, Castillo & Pi-Sunyer 1991). Other researchers noted a significantly higher TEF in subjects who consumed four smaller meals compared to those who ate one large meal (Leblanc, Mercier & Nadeau 1993). But other studies found no significant differences in TEF for different meal frequencies (Bellisle 2004).
Measuring Meal Patterns
Studies have found that irregular meal frequency may lead to obesity over time. Researchers who compared the effect of eating anywhere from three to nine meals per day versus regularly eating six times per day found that irregular patterns produced a lower TEF (Farshchi, Taylor & Mcdonald 2004). A more recent study conducted by the same researchers also noted that subjects with irregular meal patterns demonstrated a lower TEF and a higher energy intake (Farshchi, Taylor & Mcdonald 2005). These findings suggest that there may indeed be a weight loss benefit (at least in terms of TEF) from eating a consistent pattern of meals or snacks throughout the day.
Meal patterns are also influenced by other factors, such as feeling full. For example, one study observed obese women who ate either two or six meals per day; in the short term, meal frequency had no major impact on energy intake or energy expenditure (Taylor & Garrow 2001). However, the researchers did find that energy expenditure was delayed when a larger meal was consumed later in the day (Taylor & Garrow 2001).
The Pitfalls of Snacking
As suggested above, one potential benefit of consuming smaller, more frequent meals each day is warding off hunger. The pitfall, however, is that excessive or unhealthy snacking can lead to overconsumption of calories, which in turn will lead to weight gain.
This is borne out by the research, which suggests that the reported total daily food intake is 25% higher in snackers versus those who do not snack (McCrory, Suen & Roberts 2002). The actual percentage may be even higher, given how common it is for people to underreport their food intake.
It will probably come as no surprise that Americans of all ages are snacking more these days. In fact, the mean number of nibbles consumed each day by people over 2 years old increased from 1.1 snacks in 1977–1978 to 1.6 in 1995 (McCrory, Suen & Roberts 2002). Although snacking may actually improve the nutrient balance in certain individuals, more often than not, the practice results in overconsumption of daily calories and energy imbalance (Bellisle 2004). To avoid these pitfalls—and to prevent weight gain—the number of calories in all snacks each day needs to be considered part of one’s daily allowance and not overlooked.
To help you and your clients make good decisions in terms of meal and snack frequency, see the sidebar “Practical Meal Strategies.” For those looking for specific recommendations in terms of food, see the sidebar “Sample Daily Meal Frequency Plan.”
The Take-Home Message
Although the jury is still out on the benefits of increasing meal frequency, we do know this much. Research suggests that a regular pattern of eating may have a metabolic edge over a more irregular meal pattern. The real benefit of eating more frequent, smaller meals over the course of your day may not be in regulating metabolism as much as it is in warding off hunger. Finally, any calories derived from nibbling and snacking need to be added to your daily caloric total and not forgotten in the scheme of things.
The important thing to do before changing your meal frequency is to determine what will get you through your day feeling satiated and energized. For some, the standard three square meals per day may suffice. However, others may find that spreading more meals over the course of the day offers real benefits in terms of warding off the munchies and keeping unwanted pounds at bay. In short, a good strategy for not eating too many calories may be consistency, planning and a full stomach.
SIDEBAR: Practical Meal Strategies
Use these tips to make good decisions in terms of balancing the calories you take in with the energy you expend each day:
- Determine Your Daily Calorie Needs. Total calories per day can be estimated using prediction equations or measured more precisely in a research setting. Most recently, handheld devices, such as calorimeters, that accurately measure resting metabolic rate (RMR) have made their way into the fitness marketplace (Nieman, Trone & Austin 2003; St-Onge et al. 2004). A food diary can also be helpful for determining the number of calories eaten each day. Online, check out the calorie recommendations included in MyPyramid at www.mypyramid.gov.
- Combine Nutrients to Ward Off Hunger. Frequency of meals may be less important in the long run than the actual content of your meals. To add nutrient density and increase satiety, incorporate a source of carbohydrate, protein and fat in each meal (Simonds 2005).
- Up the Daily Sources of Protein. A lean protein source should be incorporated into each meal, for two reasons. First, protein provides a higher satiety value than carbohydrate and fat (Simonds 2005). Second, protein has the highest thermic effect (TEF) of any food type, meaning protein burns more calories than carbohydrate and fat when broken down and stored in the body (Jéquier 2002).
- Plan Your Meals and Snacks. Be creative with what is packed into your daily feedbag. Always bring along an extra snack to ward off hunger when you are at your lowest point in the day (usually late afternoon). It’s much easier to avoid high-calorie treats if you have a healthy substitute on hand when you are feeling vulnerable and famished! See “Sample Daily Meal Frequency Plan” on page 86 for a whole day’s worth of healthy choices.
Be Consistent in Your Choices. Eating well is a concerted effort, but it yields the benefit of feeling good. Making consistent, healthy food choices gets you closer to overall well-being.
SIDEBAR: Sample Daily Meal Frequency Plan
Patricia Simonds, MS, RD, CSCS, is a registered dietitian with a master’s degree in kinesiology. She is currently a senior lecturer at Emory University in Atlanta, specializing in nutrition and physical education. Contact her at firstname.lastname@example.org.
Bellisle, F. 2004. Impact of the daily meal pattern on energy balance. Scandinavian Journal of Nutrition, 48 (3), 114–18.
Bellisle, F., McDevitt, R., & Prentice A. 1997. Meal frequency and energy balance. British Journal of Nutrition, 77 (Suppl. 1), 57S–70S.
Farshchi, H., Taylor, M., & Macdonald, I. 2004. Decreased thermic effect of food after an irregular compared with a regular meal pattern in healthy lean women. International Journal of Obesity, 28, 653–60.
Farshchi, H., Taylor, M., & Macdonald, I. 2005. Beneficial metabolic effects of regular meal frequency on dietary thermogenesis, insulin sensitivity, and fasting lipid profiles in healthy obese women. American Journal of Clinical Nutrition, 81, 16–24.
Jéquier, E. 2002. Pathways to obesity. International Journal of Obesity, 26 (Suppl. 2), 12S–17S.
Jéquier, E., & Tappy, L. 1999. Regulation of body weight in humans. Physiological Reviews, 79 (2), 451–80.
LeBlanc, J., Mercier, I., & Nadeau, A. 1993. Components of postprandial thermogenesis in relation to meal frequency in humans. Canadian Journal of Physiology and Pharmacology, 71 (12), 879–83.
McCrory, M., Suen, V., & Roberts, S. 2002. Biobehavioral influences on energy intake and adult weight gain. Journal of Nutrition, 132 (Suppl.), 3830S–34S.
Nieman, D., Trone, G., & Austin, M. 2003. A new handheld device for measuring resting metabolic rate and oxygen consumption. Journal of the American Dietetic Association, 103(5), 588–92.
Poehlman, E., & Melby, C. 1998. Resistance training and energy balance. International Journal of Sport Nutrition, 8 (2), 143–59.
Simonds, P. 2005. Keeping hunger at bay. IDEA Fitness Journal, 2 (6), 86–89.
St-Onge, M., et al. 2004. A new hand-held indirect calorimeter to measure postprandial energy expenditure. Obesity Research, 12 (4), 704–9.
Tai, M., Castillo, P., & Pi-Sunyer, F. 1991. Meal size and frequency: Effect on the thermic effect of food. American Journal of Clinical Nutrition, 54, 783–87.
Tappy, L. 1996. Thermic effect of food and sympathetic nervous system activity in humans. Reproductive Nutrition Development, 36, 391–97.
Taylor, M., & Garrow, J. 2001. Compared with nibbling, neither gorging nor a morning fast affect short-term energy balance in obese patients in a chamber calorimeter. International Journal of Obesity, 25, 519–28.