Eating high-glycemic load diet could increase depression and fatigue

A high-glycemic load diet is linked to higher depression symptoms, fatigue and mood disturbance compared to a low-glycemic load diet, a new study finds.
The glycemic load (GL) helps people assess how food portions affect blood sugar levels, and can be useful for people with diabetes who may be unsure about how a meal could affect their management.
Foods with a high GL are those with a high carbohydrate value that influence blood glucose levels quickly. Bread, rice and many breakfast cereals are notable examples of foods with a very high GL.
In this new study, researchers from Fred Hutchinson Cancer Research Centre, Seattle, US examined several hypotheses regarding diet and mood. They also investigated the extent to which carbohydrate intake could affect mood.
They recruited 82 participants who were either a healthy weight or overweight/obese, none of whom had diabetes. The, they were randomised to different groups testing the impact of eating high- and low-glycemic load diets over 28 days.
All participants filled in reports evaluating their mood and energy levels during the interventions. Additionally, mood was assessed using the Profile of Mood States subscales and the Centre for Epidemiological Studies – Depression (CES-D) scale at the beginning and end of the studies.
The researchers observed that participants who ate a high-glycemic load diet had a 38 per cent higher score for depressive symptoms, a 55 per cent higher score for total mood disturbance and a 26 per cent higher score for fatigue/inertia.
When analysing subgroups, overweight/obese participants had a 40 per cent higher score on the CES-D scale compared to participants of a healthy weight.
“Given the current rates of obesity and depression, these study results are important for the consideration of public health care practitioners and policy makers when examining diet patterns not only of people who want to maintain healthy weight and mood, but particularly overweight and obese individuals,” said the study authors.
A significant strength of this study is that it is a randomised controlled trial, which has much more clinical use than observational studies for research into diet interventions.
If you have access to blood glucose testing supplies, you could test which glycemic food values help you keep good control of your blood sugar. Testing before eating, two hours afterwards and four hours afterwards can help you assess how your body has responded to that food.
It is worth noting, though, that some people with diabetes will have different tolerance to carbohydrate in food than others.
The study appears in the online journal Science Direct.