Research Reviews

Research Review: Bite slowly, eat less

Can tracking bites per minute help you eat fewer calories?

by Helen Kollias

In this study researchers tracked bites per minute rate as a way to determine eating speed.  And they found that eating slower is a simple, but effective way to reduce how many calories you eat in a meal.

Sometimes solutions to problems are simple.

In debt? Spend less.

Hate your job? Quit.

Have no free time? Stop watching 3 hours of TV a night.

Oh, I guess I should mention: Simple doesn’t mean easy.

A few weeks ago, I went to the Lean Eating PN seminar at Bang Fitness in Toronto. The facilitator, Coach Krista Scott-Dixon, asked Lean Eaters attending about their most significant “a-ha” moments and challenges. Most folks were struggling with two simple — but difficult — lessons:

  • eating slowly; and
  • eating until 80% full.

On the other hand, I’m sure the Scrawny to Brawny group would say the most difficult thing is to eat as much food as they can nearly all the time.

Two relatively easy concepts: how fast you eat; how much you eat.

Two difficult things to do: change your eating speed; change how much you’re used to eating.

Today’s review will look at bpm — no, not beats per minute, bites per minute.

Eat slower, eat less

Many studies show that people who eat faster are heavier than people who eat slowly [1-5]. People who trained themselves to eat more slowly ate less, and lost weight [6,7].

Most research is on weight loss, since it’s a much bigger health issue than weight gain, but those of you interested in weight gain (like all you Scrawny to Brawnies) can also use eating speed to your advantage. By purposely eating faster you’ll eat more, helping you gain weight.

(Also: eat while distracted, Brawnies; that too will help you eat more.)

How can you tell if you’re eating faster or slower than you normally would? And how much faster or slower do you need to eat to make a difference?

Monitoring eating speed

A while back I reviewed an article showing that eating slowly decreased caloric intake while leaving people feeling more satisfied.

That study used a scale with a real time graph as biofeedback telling people to slow down. People tried to eat slowly enough to keep the weight of the food on their plates the same as the ideal weight, according to the graph.

Okay, so eating with your plate on a scale while watching a monitor graphing every change in weight is one way to eat faster or slower, but it seems a little involved.

Research question

This week’s review looks at the effectiveness of another method for changing eating speed: monitoring bite rates.

Scisco JL, Muth ER, Dong Y, Hoover AW. Slowing bite-rate reduces energy intake: an application of the bite counter device. J Am Diet Assoc. 2011 Aug;111(8):1231-5.

One way to eat slower is to take more time between bites (slowing bite rate).

For example, if you normally take 4 bites in a minute, then you would aim for 2 bites in a minute, with longer breaks between bites. (Obviously, each bite has to stay the same size.)

This study examined whether university students (average age of 19.7) could be trained to take fewer bites per minute , and whether that decreased how much food they ate at a sitting.

Methods

There were 30 students in total (23 females and 7 males); 10 of whom were obese (BMI≥25).

The test food was frozen mini-waffles. These were likely chosen because they’re quick to prepare, uniform, easy to divide into bite-size pieces (they even have a grid), and something university students tend to eat.

Each mini-waffle was cut with 72 bite size pieces per serving. Participants had only a fork as a utensil, so each bite would be exactly the same size.

(Sadly, another reason frozen waffles were chosen were because most Americans tend to eat bread-like foods — maybe bite-rate isn’t the biggest issue, but malnourishment.)

On the first visit the students sat down in front of the plate of pre-cut waffles placed on a table with a hidden scale. They were told to eat one bite at a time, but given no information about how fast or slowly they were eating. Meanwhile, scientists recorded subjects eating, measuring bite rates, via a live video feed.

As soon as the students had had enough waffles, they told the scientist they were finished and completed a questionnaire on how full or hungry they felt.

The next two visits were basically the same, but participants watched a monitor that graphed how many bites they were taking.  The students were asked, randomly, either to watch the monitor with no specific goal, or to eat at half the speed as their previous visit.

Thus there were three test groups:

  1. Baseline visit: eat waffles one bite at a time, with no feedback or specific goal
  2. Feedback visit: eat waffles one bite at a time, while watching a monitor graphing bites
  3. Slow bite rate visit: same monitor feedback condition, but with a target rate on the monitor (50% of the baseline)

Results

Purposely eating waffles more slowly (slow bite rate visit) meant eating fewer waffles (about 70 calories less — see Figure 1) than just watching feedback of how many bites per minute.

Knowing without purpose = no change

Just knowing eating speed without a clear goal of slowing down didn’t change total calories eaten very much. (See Figure 1 below.) It’s like having your driving speed measured without any idea of what the speed limit is.

Figure 1 bite rate calories baseline Research Review: Bite slowly, eat less
Total calories eaten during the Feedback visit and Slow-Bite rate visit

You’d think eating while watching a monitor of your eating speed might change your eating, but it didn’t. No change in number of bites, total time of eating or bite rates.

Knowing with purpose = change

However, the group instructed to slow their bite rate down took fewer bites (Figure 2a), took longer to eat the meal (Figure 2b), and of course had a slower bite rate (Figure 2c)

Figure 2 total eaten by bite group Research Review: Bite slowly, eat less
Figure 2a: Total number of bites, by group
Fig 2b total meal time x group Research Review: Bite slowly, eat less
Figure 2b: Total meal time, by group
Fig 2c bite rate x 3 groups Research Review: Bite slowly, eat less
Figure 2c: Bite rate, by group

One more interesting thing came up. Students who ate more than 400 kcal at the first visit had the biggest decrease in calories eaten (164 kcal) at the slow bite rate visit, while students that ate fewer than 400 kcal had no change in calories eaten when they slowed down (Figure 3).

Fig 3 high vs low consumers x groups Research Review: Bite slowly, eat less
Figure 3: High consumers vs. low consumers, by group

This suggests that purposely trying to eat more slowly may have the biggest impact on people who normally over-eat significantly because they rush.

Eating faster or slower had no impact on ratings of hunger or fullness, nor did bigger people eat more.

Conclusion

Tracking how many bites you take in a minute will not decrease how many calories you eat unless you are purposely trying to slow down.

This study used 50% slower or less bites per minute, which worked out to about 15 minutes to eat around 400 kcal.

For some reason eating slower only works on people who eat more calories at a sitting. Maybe the people who normally eat less are able to feel full faster than those who eat more. We won’t know the exact reason until we do more studies.

On the other hand, if you want to eat more, try to double how many bites you take in a minute. (Or more. What the heck.)

There’s even a device that will track how many bites you’ve taken. You wear it on your wrist, and it detects when the wrist rolls — as an pattern of a bite. Maybe special forks will come out next.

Bottom-line

Eating slower is a simple way to reduce how many calories you eat in a meal. But you may struggle with slow eating if you don’t have a clear way to track it.

To slow yourself down, track how many bites you take in a minute. Next time you eat, try to cut that bite rate in half. At the very least, concentrating on how many bites you’re taking in a minute will make you more conscious of your eating.

For anyone who wants to gain weight try the opposite: Eat fast and be distracted when you eat.

bitecounterdantetktk Research Review: Bite slowly, eat less

References

Click here to view the information sources referenced in this article.

Learn more

To learn more about making important improvements to your nutrition and exercise program, check out the following 5-day video courses.

They’re probably better than 90% of the seminars we’ve ever attended on the subjects of exercise and nutrition (and probably better than a few we’ve given ourselves, too).

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