Dr's Casebook column with Dr Keith Souter: Sleep well to reduce junk food cravings

Was it when you felt in need of a treat or when you just couldn’t be bothered with eating healthily? A lot of people resort to junk or nutrient poor food when they are tired, especially if they are sleep-deprived. It seems that is when self discipline is likeliest to slip.

Junk food is unhealthy because it is high in calories, saturated fats, sugar, and sodium while lacking essential nutrient, fibre, vitamins, and minerals. It is well known that eating highly processed foods a lot of the time leads to chronic health issues, including obesity, heart disease and type 2 diabetes. Too much fat in the diet has also been shown to cause inflammation in the body.

A study from New York looked at whether sleep deprivation is associated with increased junk food consumption. They found that there certainly was an association, but very interestingly, they found that different parts of the brain light up depending on whether or not people had slept well. It really does seem that junk food appeals to the tired brain.

The researchers compared functional MRI brain scans of 25 young male and female volunteers when they were shown images of healthy and unhealthy foods after five nights of restricted sleep, when they were allowed no more than four hours, or after five nights of regular sleep, when they could sleep for up to nine hours. Images of healthy foods included oatmeal, fruits and vegetables. Images of unhealthy or nutritionally poor food included pepperoni pizza and chocolates and other sweets.

The different types of food seemed to activate different parts of the brain.

When the volunteers were sleep deprived, the unhealthy foods stimulated parts of the brain that the healthy foods did not. When they were well slept, the response in that part of the brain did not occur.

And when the individuals were questioned, they admitted that when they were sleep deprived they found the unhealthy options more appealing than the healthy ones. Further, they actually ate more and they ate more fat when they were sleep deprived.

This goes in line with other studies on sleep deprivation, which have shown that sleep deprivation makes people eat more and that there seems to be a greater desire for salty and sweet foods.

All of this is fascinating, since it suggests that the sleep cycle is linked with appetite regulation and potentially with obesity and other conditions I mentioned above. This is important for everyone but particularly for youngsters, who for one reason or another in these pressured times may not get sufficient sleep. Getting plenty of sleep may help their health in so many ways.