Snacking Behaviour

Can genes influence eating habits?

Snacking refers to what we eat outside of our main meals. It may come as no surprise that the rate at which we snack and the quantity of food that we snack on varies from person to person.

Research suggests that our snacking behaviour is partly influenced by our genes and the degree to which we inherit our eating habits is thought to be around 20-30% [1] Jump to reference section: [1] .There are a number of genes scientists have identified as affecting eating behaviours, some of which we will explore in this report. It is important to note that eating behaviour is a complex trait with many hundreds of genes playing a role and the genes explored below are some of the most well studied.

Why don’t I feel full?

It’s likely that your genes can have some effect on how satiated (full) you feel after a meal. If a meal does not fully satiate you, this may result in more frequent snacking throughout the day to make up for it. Studies have shown that the genetic variant rs9939609 in the FTO gene may affect this. The FTO gene carries the instructions for a protein which has been shown to regulate appetite. Scientists have established that individuals with an A allele at this position are less likely to feel full after a meal [2] Jump to reference section: [2] .

Why am I hungry so soon after my last meal?

Even if a meal does fully satiate you. It might not be long until you are hungry again. This means you are more likely to eat in between meals. Leptin is a hormone which also regulates how full we feel. Studies have shown that a mutation on a leptin receptor gene - LEPR - can directly affect how often we snack. The genetic variant rs2025804 has been shown to be linked to snacking behaviour.

Scientists established that people with two copies of the G allele at position rs2025804 are twice as likely to show 'extreme snacking behaviour' (which is defined as consuming more than 15% of their energy intake as snacks in between meals)[3] Jump to reference section: [3] .

Fighting cravings?

Sometimes it can be important for us to fight the urge to eat snacks. Whilst the mechanisms behind self-restraint are not purely genetic, there is evidence of some genetic mutations making self-restraint with regards to snacking more difficult.

Researchers have found that a genetic mutation at the variant rs1051168 on the NMB gene can affect how well we are able to exercise self-restraint in our eating habits [4] Jump to reference section: [4] . Individuals with two copies of the T allele version of rs1051168 have been identified as less likely to engage in self-restraint when it comes to eating.

What does this all mean for me?

Whilst there is compelling evidence that your genes can affect your eating behaviours, it’s important to remember that in these studies genetics did not account for all the variation we see in snacking habits. The degree to which we inherit our snacking behaviours is thought to be around 20-30%, with other factors such as environment and lifestyle also playing an important role.