Meal Frequency & Weight Loss
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 con┬¡sumption. 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 &
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
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
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
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.
in represents the amount of food you consume each day,
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 (J├®quier & 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
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
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
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
- 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 (J├®quier 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.
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 [email protected]
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