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By Alex Ruani, Research Director

Do frequent meals raise your metabolism?

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Summary 2

Here’s what we’ll cover in this report:

A typical scenario to consider

The risks of giving blanket advice

The meal frequency dilemma

What do intervention studies say?

More recent evidence

Back to the basics of metabolism

The 24-hour metabolic formula

Basal metabolic rate and fat-free mass go hand-in-hand

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Summary (continued)

3

Can increasing meal frequency raise your basal

metabolic rate?

What happens to your metabolism when you skip meals?

Understanding the thermic effect of food

Can frequent meals increase the thermic effect of food?

Other supporting evidence

Your key takeaways

Learn more

References and resources

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A scenario to consider 4

Here’s a scenario for you to consider:

A gym member asks the trainer: “My goal is to lose

body fat. How should I go about eating?”

The trainer responds: “You need to eat every 2 or 3

hours, or at least six meals a day. That will increase

your metabolism and enhance fat loss.”

Does this sound familiar to you? How many times have

you heard this?

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Let’s take a step back 5

Before we examine whether there’s any truth to the

trainer’s response, I’d like to say that prescribing blanket

advice to everyone, without any consideration of

someone’s individual biochemistry, physiology, athletic

status, eating history and preferences, is far from ideal

and can do more harm than good. What works for a

trainer or one client, may not work for another client.

Now, back to the order of the day.

Would six meals a day really increase your metabolism

and enhance fat loss?

Let’s see!

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The meal frequency dilemma 6

In the health and fitness circles, particularly bodybuilding,

there’s a persistent belief that eating small frequent meals

throughout the day leads to increases in metabolic rate

and fat loss.

But, is that really the case?

Unfortunately, no.

The theory that frequent meals provide you a metabolic

advantage has been disqualified by a 1997 meta-

analysis of epidemiological studies on eating frequency

(Bellisle et al, British Journal of Nutrition).

The researchers also found that more meals did not

equate to more fat loss.

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What do intervention studies say? 7

Several intervention studies where meal size and

frequency was modified – whilst keeping the daily caloric

intake static – found no differences in metabolic rate (i.e.

24-hour caloric expenditure) and no additional weight loss

from eating more regularly (Verboeket-van de Venne,

Westerterp, 1991 and 1993; Smeets, Westerterp-

Plantenga, 2008; Cameron, Cyr, Doucet, 2010).

Subsequent studies concluded the same.

A 2013 study published in the journal Obesity found that

six meals a day didn’t increase 24-hour energy (calorie)

expenditure or fat oxidation (burning). Moreover, the

scientists noticed that six meals a day may actually

increase hunger and the desire to eat (Ohkawara et al).

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More recent evidence 8

A meta-analysis published in 2015 by the Oxford University Press found that meal frequency does not affect metabolism (i.e. 24-hour calorie expenditure) and that body fat percentages are not connected to the number of meals consumed in a day.

The current scientific consensus is that there are benefits derived from manipulating meal frequency. But a faster metabolism is not one of such benefits!

If you’re a competitive athlete, for example, working out your precise nutrient timing, dosing and ratio is key to trigger body composition adaptations, enhance performance, and speed up recovery. However, there is no evidence to support the idea that multiple meals speeds up your metabolic rate.

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Back to the basics of metabolism 9

There are five primary factors that affect your overall energy

expenditure (EE) throughout the course of 24 hours (24EE):

Your basal metabolic rate (BMR): the calories you spend at

rest to keep your heart beating, your lungs breathing, etc.

The thermic effect of the food you eat (TEF): the calories

your body uses to digest, assimilate, and metabolise food.

Exercise thermogenesis (EEx): the calories you spend during

exercise.

Non-exercise activity thermogenesis (NEAT): the calories you

spend from spontaneous movement.

Cold thermogenesis (CT): the calories you spend when

exposed to colder temperatures.

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We can summarise the above factors in this formula:

24EE = BMR + TEF + Eex + NEAT + CT

To find out whether or not increasing your meal frequency

leads to an increase in your metabolic rate, we need to

see if meal frequency has an effect on any of these five

factors.

Logically, increasing your meal number, whilst keeping

your daily caloric intake static, will not directly alter EEx,

NEAT or CT, so we can cross those three off from our list of

analysis. This leaves us with BMR and TEF as the

supposedly modifiable factors.

The 24-hour metabolic formula 10

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Basal metabolic rate, fat-free mass 11

Besides exercise, the main driver of your caloric

expenditure in a day (24EE) is your fat-free mass (FFM) –

that is, your total body mass, without the fat (Avussin,

Bogardus, 1992). Fat-free mass includes your muscles,

organs, skin, bones, ligaments, tendons, and water content.

The larger your fat-free mass (FFM), the higher your BMR

(i.e. the calories you spend at rest).

This means that the majority of the energy expended over

the course of a day is dictated by your BMR, which is

correlated to how much FFM you have.

So, in theory, meal frequency wouldn’t increase your BMR.

But what does the scientific literature say?

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Can frequent meals raise BMR? 12

A 2012 study conducted by Munsters and Saris found the

opposite: the participants on a low-frequency meal plan

had a slight increase in resting energy expenditure (BMR)

compared to the participants on a high-frequency meal

plan.

The study researchers didn’t see any differences on fat

oxidation between the two groups of participants.

Quite surprisingly, they found that the low-frequency meal

plan increased satiety and reduced hunger ratings during

the day.

Now, that’s an interesting twist!

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What happens when you skip meals? 13

On the other side of the spectrum, can periods of “not

eating” depress your metabolic rate?

It appears that the answer depends on whether or not you

compensate for those calories later on.

A 2005 study showed that alternate-day fasting (not

eating every other day) does not result in a decrease in

metabolic rate after 22 days of being on such plan,

whereby the participants were instructed to eat twice as

much food on non-fasting days, to compensate (Heilbronn

et al, 2005).

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What happens when you skip meals? 14

When you significantly drop the calories that you eat in a

given period of time, your metabolic rate declines slightly.

However, this overall decline is based on your total caloric

intake (rather than meal frequency) during such period

(Verboeket-van de Venne, Westerterp, 1993).

Continued

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The thermic effect of food (TEF) 15

It’s true that digesting a meal raises your EE (energy

expenditure) slightly.

This is known as the thermic effect of food (TEF).

The thermic effect of food is the energy (calories) that

your body spends above your BMR to process, use and

store the food you eat.

TEF is averaged out to approximately 10% of someone’s

total caloric intake.

For example, if you ingest 2,000 calories over the course

of a day, around 200 calories will be lost as heat through

essential processes like absorption, digestion, and storage.

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Can frequent meals raise TEF? 16

According to research, increasing meal frequency has no

influence on the thermic effect of food (Taylor and

Garrow, 2001).

It’s the total amount of food consumed that determines the

amount of calories expended for food processing and

assimilation.

For example, eating three meals of 600 calories each will

cause the same thermic effect as eating six meals of 300

calories each.

Meal frequency makes no difference.

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Other supporting evidence 17

Interestingly, some of the studies we mentioned before

found that lower meal frequencies actually increased the

thermic effect of food (not the other way around) and that

fat oxidation remained unchanged (Bellisle et al, 1997;

Munsters, Saris, 2012).

This is the opposite of what many fitness professionals

believe to be the case.

Overall, the scientific evidence shows that increasing meal

frequency doesn’t raise the thermic effect of food.

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Your key takeaways 18

Manipulating nutrient timing and frequency in an athlete’s

diet can trigger favourable competitive adaptations. But

increased metabolic rate is not one of them.

There isn’t solid evidence suggesting that increasing meal

frequency can raise metabolic rate and/or body fat

oxidation.

Whether you eat three times per day, or six or more, the

effects on metabolic rate will essentially be the same.

Also, the thermic effect of food (TEF) is not affected by

increasing the number of meals.

In the end, it comes down to your own personal preference

and fitness or performance goals.

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Learn More 19

Further readings:

Science Report. Fasting and Training: Good or Bad?

When Skipping Breakfast May Actually Be Good For You

3 Little-Known Changes You Can Trigger With Intermittent

Fasting

Can Shivering Help Burn Fat?

Relevant courses:

Advanced Sports and Exercise Nutritional Advisor

Advanced Clinical Weight Loss Practitioner

Fitness Nutrition

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References and Resources I 20

Meal frequency and energy balance. Bellisle et al, 1997.

British Journal of Nutrition.

Influence of the feeding frequency on nutrient utilization in

man: consequences for energy metabolism. Verboeket-van

de Venne and Westerterp, 1991. European Journal of

Clinical Nutrition.

Acute effects on metabolism and appetite profile of one

meal difference in the lower range of meal frequency.

Smeets and Westerterp-Plantenga, 2008. British Journal of

Nutrition.

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References and Resources II 21

Increased meal frequency does not promote greater weight

loss in subjects who were prescribed an 8-week equi-

energetic energy-restricted diet. Cameron and Doucet,

2010. British Journal of Nutrition.

Frequency of feeding, weight reduction and energy

metabolism. Verboeket-van de Venne and Westerterp,

1993. International Journal of Obesity and Related

Metabolic Disorders.

Effects of increased meal frequency on fat oxidation and

perceived hunger. Ohkawara et al, 2013. Obesity, Silver

Spring.

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References and Resources III 22

Effects of meal frequency on weight loss and body

composition: a meta-analysis. Schoenfeld, Aragon, and

Krieger, 2015. Oxford University Press.

A brief overview of human energy metabolism and its

relationship to essential obesity. Ravussin and Bogardus,

1992. American Journal of Clinical Nutrition.

Effects of meal frequency on metabolic profiles and

substrate partitioning in lean healthy males. Munsters and

Saris, 2012. PLoS One.

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References and Resources IV 23

Alternate-day fasting in nonobese subjects: effects on body

weight, body composition, and energy metabolism.

Heilbronn et al, 2005. American Journal of Clinical

Nutrition.

Compared with nibbling, neither gorging nor a morning fast

affect short-term energy balance in obese patients in a

chamber calorimeter. Taylor and Garrow, 2001.

International Journal of Obesity and Related Metabolic

Disorders.

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This content was brought to you by The Health Sciences Academy.

Passionate about changing people’s lives through science and digital education.

The Author

Alex Ruani leads the research division at The Health Sciences Academy, where she and her team

make sense of complex scientific literature and translate it into easy-to-understand practical concepts

for students. Alex researches genetics of nutritional diseases and obesity at Harvard University and

nutritional sciences at Cornell University, and is a research scientist pursuing a Ph.D. Alex is also a

REPs qualified personal trainer who coaches elite athletes.

To learn more, visit

www.FreeNutritionCourse.org