Throughout the day our blood sugar levels naturally go up and down, depending on how much food we eat, whether or not we exercise, and how well our bodies are able to convert blood sugar into energy. Often, when our blood sugar is low, we feel lacking in energy and hungry, and eating a meal or snack helps us return to normal.

But many of us will be familiar with a feeling of hunger that doesn’t quite go away, even after eating a meal.

For people with type 2 diabetes, this feeling is associated with blood sugar that is especially low or high outside of a healthy range. But even fluctuations within a healthy blood sugar range can impact how hungry we feel and how much food we eat. 

‍How does blood sugar affect appetite?

Glucose is like fuel for the body. After eating, digestion helps break down foods and glucose gets transferred into the blood, causing a blood sugar spike. From there, the blood can transport this fuel around the body and transfer it to cells where it can be used as energy. As the body uses this energy, blood glucose levels gradually go down, until the point where the body requires more food to turn into fuel – often this happens around meal times.

This feeling of hunger comes as the body releases a stress hormone when its blood sugar levels start to get low triggering warning signs that can include symptoms like shakiness, difficulty concentrating, and headaches,[1] as well as a desire to eat.

The only way to find out your exact blood sugar level is to take a test that measures it. However, being aware of the feelings associated with high and low blood sugar can help give an idea of where your body is in the cycle.

‍Why do I feel hungry all the time?

There are many factors that can lead to feelings of hunger and most of these will change from day to day. However, some people may be more susceptible to persistent feelings of hunger than others.

People with very low blood sugar after a few hours of eating are likely to experience greater hunger

Wyatt et al., Nat Metab

One study has found that people whose blood sugar levels fall very low hours after eating are likely to experience greater hunger,[2] than those whose blood sugar levels remain relatively stable. Inevitably, people who experienced bigger dips were more likely to reach for a snack or meal sooner and to eat more food throughout the day than those with more stable blood sugar levels. 

Researchers found that genes determined whether or not people were likely to experience large dips in blood sugar. However, people did not experience exactly the same scale of dips every day meaning that other factors, like meal choices and activity levels, also play a role.

Why is my blood sugar high when I am hungry?

Sometimes having high blood sugar can also cause feelings of hunger, as it is a sign that the body cannot turn all food being digested into fuel. This is common among in people who have diabetes if the body is not making enough insulin or cannot use the insulin it is making properly. 

Insulin is responsible for transferring sugar from the blood to the cells and if this doesn’t happen correctly blood sugar levels remain high but the cells lack energy, even after eating. The body can interpret this lack of energy as a sign it needs to eat more, resulting in feelings of hunger. 

This creates a vicious cycle where high blood sugar causes problems with insulin and also increases feelings of hunger encouraging excessive eating, which raises glucose levels even higher.

Food addiction

Feelings of hunger are not always triggered by physical stimuli like blood sugar levels. For many of us food is strongly associated with a sense of comfort, reward, and happy memories. Foods can also be addictive, especially if they are high in fat, sugar, and salt.[3]

As such, there can be a difference between always feeling physically hungry and always wanting to eat. Persistent feelings of wanting to eat, even when you are already full, could be a symptom of food addiction. 

Typically, food addiction involves binge eating behaviours, strong cravings, hiding eating from others, feelings of guilt after eating, or lack of control around food. As well as being mentally challenging, these behaviours can cause weight gain and other side effects.

However, it is possible to overcome food addiction and reestablish a healthy relationship with food.

‍How to keep your blood sugar stable

It is normal for your blood glucose levels to fluctuate through the day within a healthy range. However, keeping your blood sugar levels as stable as possible—and avoiding big spikes or troughs—will help reduce hunger and make you feel healthier overall. There are steps you can take to help you do this.

• Eat foods that help regulate your blood sugar: Many foods are thought to have specific properties that can help regulate blood sugar,[4] including vegetables, nuts, seeds, beans and lentils, oats, yoghurt, eggs, and more. Overall, it’s best to eat a healthy, balanced diet with reasonable portion sizes and regular meals. Foods to limit or avoid include sweets, white bread, pasta, and potatoes as they can trigger post-meal spikes.
• Pay attention to your exercise routine: Exercise has an impact on blood sugar levels. Short bursts of high-intensity exercise have been found to have a positive impact on blood glucose for up to 3 days.[5] Exercise can also increase insulin sensitivity for up to 24 hours after the activity, helping to reduce hunger caused by high blood sugar. However, there is some debate over whether it is best to exercise before eating or after. For many people, the best option will come down to individual preference. Try experimenting with both options to see what feels comfortable. 
• Rethink food cravings: Everyone experiences food cravings from time to time but if they are too frequent it can become problematic. To find ways to manage food cravings you need to better understand what is triggering them. This might mean changing your routine, taking a mindful approach, or finding healthy alternatives.
• Prioritise sleep and mental wellbeing: Aside from blood sugar levels, fluctuations in hormones can also impact how hungry you feel on a daily basis. Factors such as lack of sleep, stress or premenstrual syndrome can all trigger hormones that lead to increased hunger and cravings.[6] To keep these in order try to prioritise healthy routines that look after your physical and mental wellbeing.

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