Experts Corner

How Does Blood Sugar Impact Sleep? 

May 8, 2023   By Sylvia North

Sylvia North is an integrative dietitian nutritionist based in Auckland, New Zealand. With expertise in women’s and metabolic health, she helps her Fearless Nutrition clients address and overcome digestive concerns and chronic inflammatory conditions. Supporting the use of nutrition and lifestyle to optimise their metabolic health – not just for weight loss, but for reduced inflammation and pain, improved energy levels and balanced hormones.

As a dietitian who sees clients for a wide range of health goals, sleep is always something that becomes part of the health discussion. When we’re not sleeping well, it’s easy to get into a damaging cycle of making poor nutrition choices – such as eating more processed foods, sugar, and alcohol, which then can worsen sleep quality overall.

Poor blood sugar control is a common nutritional problem

One way nutrition can support better quality sleep is by balancing blood sugar levels. Blood sugar problems are one of the most common nutritional issues in Westernised societies due to increasing rates of insulin resistance and hyperinsulinaemia (excessively high insulin levels).

People with dysfunctional insulin and blood sugar regulation are more vulnerable to experiencing both high and low blood sugar. On top of that, excessive stress, eating processed foods that are high in refined carbs and sugar, inconsistent eating patterns, and inadequate food intake can also lead to blood sugar peaks and crashes across the day as well as later on at night when trying to sleep. 

Low blood sugar levels can disrupt sleep  

A common cause of sleeping difficulties is low blood sugar levels that develop throughout the night. As blood sugar levels fall, the body makes stress hormones, including adrenaline, to raise blood sugar levels to a healthy range required to support essential physiological functions. And this stress response is practically the opposite of the state we need to be in for deep and restful sleep.

The result might include waking up during the night, having difficulty falling back to sleep, and perhaps needing to have something to eat.

One of the best ways to find out if this might be your issue is doing an experiment with a continuous glucose monitor such as the Freestyle Libre system, which can detect your glucose patterns over the night.

What you eat during the day will catch up with you at night

A whole-food low glycaemic way of eating is beneficial for supporting blood sugar stability and insulin sensitivity. This approach means minimising meals and snacks high in carbohydrates and sugars and including an adequate amount of foods rich in protein, fat, and fibre.

When we combine whole-food carbs with protein, fat, and fibre, sugar is released into the blood more slowly, leading to more stable blood sugar levels across the day. Including enough protein and fat in the diet is also essential for keeping you feeling satisfied, so that blood sugar levels don’t fall too low and trigger a stress response. 

Eating large carbohydrate portions such as rice or pasta in the evening can lead to excessively high blood sugar that night. In individuals with hyperinsulinaemia in insulin resistance, this may then be followed by a significant drop in blood sugar later on while trying to sleep. Having a plate that balances the carbohydrate-rich food with a serving of protein, healthy fat, and plenty of non-starchy vegetables can mitigate the blood sugar spike, leading to better metabolic health across the night. 

A tip for bedtime snackers

People who eat their evening meal early, or those who struggle to eat enough across the day, may also benefit from a bedtime snack that is high in protein and fat, and low in carbs. Such as? Fruit and yoghurt, a chia seed pudding with fruit, nuts and coconut milk, leftover chicken or meat, or nut butter with an apple. Sweet dreams!

Want more advice from the experts? Check out our recent blog post, How to Create a Strong Sleep Foundation for Your Child. 

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