Is the Sweet Tooth real?

  Nell Team
Nutrition Weight Loss

Sugary treats may taste good, but the human body doesn't need sugar to survive.

We need carbohydrates, which the body breaks down into sugars. But there's really, unfortunately, no biological need to reach for _another _slice of cake/ scoop of ice cream / handful of gummy bears.

Our brains and hormones often manage to convince us otherwise though. Some of us just seem to have a sweet tooth we can't escape.


If this sounds familiar, and you find it particularly hard to resist your sugar cravings, the root of your sweet tooth could lie deep down in your DNA. These "sweet tooth" genes help to determine how much sugar you eat and even what kind of sweet treats you prefer.

Which genetic variations affect sugar intake?

Humans share largely identical DNA. But in the few places where genetic variations occur, differences between you and the next person emerge.

These genetic variations help us to understand the predispositions that affect our individual eating habits, weight and overall health. And there are two genetic variations known to affect how much sugar a person consumes:


Glucose transporter 2 — or GLUT2, for short — controls the entry of glucose (the sugar our bodies use for energy) into our cells. Researchers believe that GLUT2 is also involved in whether or not we feel full, based on our blood sugar levels.

On top of this, there's a particular variant of the GLUT2 gene that's associated with regular consumption of sugars. One study found that people with this variant (Thr110Ile) had a significantly higher intake of sugars on a daily basis.


FGF21 is a cytokine hormone. It promotes glucose uptake by fat cells and may also signal to the brain's hypothalamus that more sugar intake is required. FGF21 is also present in the adipose tissue, where energy is stored as fat, and helps to increase GLUT1 transport expression — allowing more glucose uptake in our cells.

Certain FGF21 gene variants are associated with increased sweet food consumption. People with a genetic variant in the rs838133 polymorphism are more likely to enjoy (and therefore consume) sweet-tasting foods. They prefer candy (sweets, chocolate or ice cream) over cake, fatty-sweet foods (like pastry) and salty snacks.

Does having a "sweet tooth" gene mean you'll be overweight?

We all know that over-eating sugar isn't good for us. Studies have shown that high sugar intake leads to increased weight gain and sugar has also been linked with a number of chronic diseases.

But a sweet tooth DNA diagnosis doesn't necessarily mean a life spent battling with your weight. In fact, there are studies to suggest the opposite.

For example, a study into the FGF21 gene found that people who carry the A allele of the rs838133 polymorphism (which is supposed to increase a person's intake of sweet treats), actually had a lower BMI and waist circumference compared with non-carriers. They also had better glycaemic control.

The study concluded that small increases in sugar consumption do not necessarily lead to obesity or glucose intolerance, even when you carry the FGF21 variant.

The key word here is small. Someone with a sweet tooth gene might find it harder than the average person to keep their sugar cravings in check. But if sweet treats are eaten in moderation, obesity isn't a genetic inevitability.

What can you do if you suspect a sweet tooth gene in your DNA?

Understanding more about your unique genetic makeup — with the help of a Nell genetic test — gives you the information you need to create a diet best suited to your DNA.

If you discover you _do _have a genetic sweet tooth, here are a few things you can do to control those sugar cravings and avoid unwanted weight gain.

Reach for fruit rather than sweets

Fruit contains some sugar, but it also contains lots of nutrients. Snacking on fruit rather than sweets will give you a little sugar fix, while helping you to maintain a healthy body weight.

Get a good night's sleep

The body produces more ghrelin (the hunger hormone) and less leptin (the hormone that helps you to feel full) in correlation with how much you sleep. This leaves you feeling hungrier after a bad night's rest and, chances are, more likely to succumb to food cravings. That's why poor sleep is associated with a higher BMI.

Adults are advised to aim for between 7 and 8 hours sleep a night. So get some decent shut-eye and you could see an improvement in your sugar-eating habits.

Stay hydrated

Drinking water has been shown to reduce feelings of hunger and increase feelings of satiety (fullness). This means having a glass of water before a meal might make you less likely to crave a dessert.

In fact, overweight adults who drank 500ml of water before a reduced calorie meal lost 2kg (or 44%) more weight over 12 weeks than those who didn't drink water before their low calorie meal.

Get on top of your sweet tooth with Nell

A genetic sweet tooth might make it more difficult to resist sugary treats and maintain your ideal weight. But — armed with knowledge of your genes — you can adapt your diet and your lifestyle, boosting your health in the process.

Get started with your Nell nutrition test today..