Our latest trait release, BDNF, memory and overeating, explored the impact of the BDNF gene on memory, highlighting the interaction between an individual's DNA, their ability to recall what they have eaten throughout the day, and their risk of overeating.

The BDNF gene plays a role in episodic memory - our ability to remember past experiences, this includes how well we remember meals we have eaten. Our ability to recall certain events can be affected by the BDNF gene variant we have, with the Met (A) variant linked to poorer episodic memory and a higher risk of overeating as a result.

This risk can also be exacerbated by high-risk lifestyle factors, such as being overweight or obese. Research has suggested that poor body composition on its own is enough to reduce episodic memory. Those who both carry the BDNF risk variant and are overweight and obese are therefore at the highest risk of impaired meal recall and overeating.

In this blog, we shed some light on the methodology and findings of one of the peer-reviewed studies we consulted when creating the insights and actions for our latest trait.

Eating and memory

The study in question was carried out by Higgs and Woodward (2009), who questioned whether watching television while eating could impair meal recall and lead to greater consumption of calories later on in the day. Their prediction was that “television watching during lunch would increase afternoon snack intake due to impaired memory for recent eating”.

16 participants were recruited for this research and were split into two groups. Using a repeated measures design, where the same participants take part in each condition, both groups were asked to eat a sandwich and crisps while watching television, before later being asked to eat the same meal while not watching television. Both groups consumed the same food and watched the same television programme. Self-reported appetite levels did not differ depending on the two separate conditions (television vs. no television).

Later on in the afternoon, the participants came back for a snack. They were provided with three plates of cookies and were told that they were allowed to eat as much as they wanted. The researchers recorded how many cookies each participant ate in each of the conditions.

Following this, the participants rated how well they remembered what they ate for lunch, from “not at all vividly” to “extremely vividly”.

The results

The results showed that when the participants ate while watching television, they had reduced recall of the meal than when they ate without watching television. This highlights that having your attention on something other than the food you are eating can cause problems with remembering what you have eaten.

Additionally, it was noted that the participants consumed more cookies in the afternoon session after eating lunch while watching television. This suggests that we have less awareness of how hungry we are when we have eaten a meal and our attention is focused elsewhere. The distraction of the participant's attention with a prior meal led to overeating later in the day.

Somewhat surprisingly, the study doesn't explicitly state how many more cookies the participants ate (in grams or as a percentage) after eating lunch while watching television, but you can see the difference between the two groups in the graph below.

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Source: Higgs, S., & Woodward, M. (2009). Television watching during lunch increases afternoon snack intake of young women. Appetite, 52(1), 39-43.

Conclusion

This study emphasised the effect that distractions can have on eating and memory of eating. Watching television may affect the encoding how the memory of the meal is encoded, causing you to not fully remember what you have consumed. As you don’t fully remember what you have eaten previously, you are more likely to overeat.  

It was suggested in this study that other activities such as listening to music or socialising may exhibit a similar effect. While some individuals may fall under the ‘unimpaired memory’ category, which means their gene variants do not reflect poorer memory, there is still the risk of overeating when distracted.

It has become increasingly common to watch television while eating a meal. This means the likelihood of overeating is increased, due to the lack of attention paid while consuming the meal. If you find that you overeat later on in the afternoon, it may be worth setting aside some time to eat your meal without any distraction to ensure you fully remember the food.

Discover your personal BDNF, memory and overeating trait

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