Woman eating

Can Being a Fast Eater Affect Weight?


Are you a fast eater? Always the first one to finish your meal, or the last? Does how quickly we eat have any influence upon how much we weigh? Hypothetically, yes. And some studies may also back this up too.

The theory

When we eat food, there are a number of factors that tell our brains that we’re full and we should put down our fork. They are:

  • Striations in the stomach. As we eat, our stomachs expand. The stomach is lined with striations that stretch out – much the same way as the wrinkles in paper bag flatten out when you blow air into it. As these striations flatten, nerve ends attached to them send signals to the brain telling us we’re filling up.
  • Hormones in the gut switch on and off. We have a few hormones that “switch on and off”, reacting to our fullness factor. Two appetite hormones known as ghrelin and leptin work together to tell our brains when we’re hungry and how much we should eat. Leptin is produced by fat and tells the brain that we don’t require much food. The fatter we are, the more leptin in circulation. Ghrelin tells our brain we’re hungry, and as we eat, less ghrelin goes into the blood.
  • The stomach, nervous system and hormones all react to food filling up in the stomach and being emptied through the gut.

This all takes time, and the body doesn’t react immediately – so if you shovel food down fast, it can trick the body into allowing more food in before it instructs the brain that you’ve had enough.

If you eat slower, it gives all these mechanisms time to catch up. The result is, you eat less. It can take around 20 minutes before your brain realises you’ve had enough food!

The science

A large Japanese study recently looked at just under 60,000 participants who were overweight at the beginning of the study, and had been diagnosed with type 2 diabetes during it.

This type of study is known as a longitudinal study, because it selects a population and observes them over a long period of time.

They observed the following traits:

  • eating speed (defined as slow, normal or fast)
  • habit of eating 2 hours or less before sleep for at least 3 times per week
  • skipping breakfast for at least 3 times per week
  • snacking between meals for at least 3 times per week
  • alcohol consumption and frequency
  • adequacy of sleep
  • smoking habits

Slow and normal speed eaters generally had smaller waists than those that ate fast.

Other studies (1,2,3,4) have also found that when people eat fast, they tend to gain weight and therefore a risk factor for diabetes (5).

Conversely, studies conducted on people that eat slower tend to consume less calories (6,7).

Most studies looking at this affect have been conducted in Japan, and therefore there is a bias toward an East Asian ethnicity- so whether this can be generalised to other ethnic groups is difficult to say.

However, the suggested mechanisms behind the reasons for this is common to us all, and so it would be reasonable to suggest that eating speed is just as applicable to other racial groups.

How to be a slower eater

Over the years, there have been a few studies looking at different eating behaviours to work out whether changing our habits, and not just what we eat, had an effect on how much weight we gained.

There’s some interesting results, and following any or all of these tips might help you succeed in you diet goals!

  • Try some simple methods to force yourself to eat slower. The following could help:
    • Don’t hold your fork. Once you’ve put the food into your mouth, put down the fork/spoon/chopsticks or whatever your implement of choice is and don’t pick it up again until you’ve swallowed.
    • Take time to chew. There are a number of people out there who believe in counting chews! There’s no real magic number on the right number of times you chew, but certainly chewing is a big factor in digestion! Your saliva contains enzymes which starts the whole process off. If you chew long enough, you should notice your food starting to taste sweeter – the reason for this is that the enzyme amylase in your saliva is breaking down the carbohydrates into smaller sugar molecules. You’ll know you’ve chewed enough if this happens.
    • Sit at the table and turn the TV off. Or put your mobile phone somewhere else. If you’re distracted whilst eating, you’re more likely to eat quicker.
    • Similarly, eating on the go will make you wolf down your food faster. Treat food time as your time – sit somewhere and enjoy it! Try mindful eating.
  • Other ideas on habit changing could include:
    • Consuming water before eating could reduce the amount you eat during meal time for some people (8)
    • Getting enough shut-eye. If your sleep is inadequate, this could mess with your hormones that dictate whether you eat more (9)
    • Making time for breakfast. Studies really do suggest that breakfast eaters are less likely to be overweight. It’s common in the UK to eat cereal or toast for breakfast, both starting the day off with a high fibre kick! Switching to wholegrain and adding some protein such as seeds, nuts, yoghurt, or peanut butter is going to help you feel fuller for longer (10)
    • Eating late at night. This is largely because, the later we eat, the poorer food choices we make – and tend to select foods higher in carbohydrate (11). It’s probably best to choose a time where after you forbid yourself food. I tend to stop eating after 7pm, but I’m a fan of prolonged daily fasting.

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So what do you think?

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