Being hungry is a sure-fire way to put anyone in a bad mood, but a recent study has found there’s a scientific connection between eating a low-calorie diet and feeling depressed. The effects of calorie restriction on mood were even more pronounced for overweight people taking part in the study.
Researchers at the University of Toronto looked at data gathered from almost 30,000 people whose eating habits were followed for around a decade. The participants were asked to complete surveys detailing their typical daily dietary choices, any diets they were following at the time, and to keep a record of any depressive symptoms.
What did the study find?
As anyone who’s attempted to follow a low-calorie diet will not be surprised to hear, participants who reported following the least calorie-dense diets scored more highly for depressive symptoms, including fatigue, difficulty carrying out ‘normal’ tasks, and decreased interest or pleasure in doing things they’d usually enjoy.
The researchers running the study, which was published in the BMJ Nutrition Prevention & Health, say this may have been due to nutritional deficiencies of key vitamins and nutrients like protein leading to worsened brain function and low mood.
What does this mean for us?
This study contradicts most other scientific evidence out there when it comes to diet choices: most other peer-review studies say that low-calorie diets could improve symptoms of depression.
The organisers of the study were keen to stress that they believe the link between calorie-restrictive diets and depressive symptoms were largely down to these diets being low in nutrients, suggesting the importance of following a nutritious, varied diet on maintaining good mental health. Scientists pulled out deficiencies in omega-3 fatty acids and vitamin B12 as being most impactful on mood.
The bottom line
This study was observational, and so cannot guarantee cause and effect. Experts commenting on the efficacy of the study said that more research is needed in this area to support the results. However, it is useful guidance to keep the nutritional value of the food you’re eating in mind when you’re planning your meals – not just the calorie count.
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