Eating foods high in fat and sugar can have negative effects on your brain, especially on the hippocampus, a region involved in memory formation and consolidation. This is the main finding of a new study published in the Journal of Psychiatric Research. The Researchers predicted that a high-fat and high-sugar diet would predict poorer performance on executive functioning tasks.
What are high-fat, high-sugar diets?
High-fat, high-sugar diets typically consist of
- pastries and baked food items,
- candies and chocolates,
- fast food meals, such as burgers, French fries, fried chicken,
- sweetened beverages such as soft drinks, energy drinks, flavored juices or sweetened teas,
- processed snacks such as chips, crackers, or snack cakes, breakfast cereals, sauces, dressings, and
- similar foods.
Executive cognitive functions refer to higher-level mental processes that are involved in
- goal-directed behaviors,
- problem-solving,
- decision-making, and
- self-regulation.
They encompass abilities such as
- planning,
- organizing,
- inhibiting impulses,
- shifting attention, and
- working memory.
What were the research methods?
The researchers conducted a meta-analysis of eight studies that used a method called Mendelian randomization to examine the causal relationship between body mass index (BMI) and depression.
They found that higher BMI was associated with higher risk of depression, regardless of whether the BMI indicated obesity or not.
They also analyzed data from two national surveys in the UK and the US and found that the prevalence of depression increased over time along with the prevalence of obesity.
They estimated that about 10% of the increase in depression could be attributed to the increase in obesity.
The authors suggest that one of the mechanisms linking obesity and depression could be the effect of high-fat, high-sugar diets on the hippocampus. Previous studies have shown that consuming such diets can impair hippocampal function and structure, leading to worse performance on memory tasks that depend on the hippocampus.
What is the hippocampus?
- The hippocampus helps you remember things and learn new things. It also helps you find your way around and navigate different places.
- The hippocampus organizes and stores your memories. Some memories are short-term, which means you only need them for a little while, like remembering what you ate for breakfast. Some memories are long-term, which means you keep them for a long time, like remembering your birthday or your favorite song. The hippocampus helps you move your short-term memories to long-term memories, so you don't forget them.
- The hippocampus helps you create a mental map of your surroundings, so you can find your way around. The hippocampus helps you remember where things are located. The hippocampus helps you recognize familiar places and people, so you don't get lost or confused.
- The hippocampus is also involved in regulating mood and emotion, and its dysfunction could contribute to depressive symptoms. Impaired memory could affect one's self-esteem, motivation, and coping skills, further increasing the risk of depression. Eating healthy foods, getting enough sleep, exercising regularly, and avoiding drugs and alcohol protects the hippocampus from damage.
The authors conclude that reducing the consumption of foods high in fat and sugar could have beneficial effects on both physical and mental health, as well as cognitive performance. They call for more research to understand the underlying biological mechanisms and to develop effective interventions.
Attuquayefio T, Stevenson RJ, Oaten MJ, Francis HM. A high-fat high-sugar diet predicts poorer hippocampal-related memory and a reduced ability to suppress wanting under satiety. Journal of Experimental Psychology: Animal Learning and Cognition. 2016 Oct;42(4):415-28. https://psycnet.apa.org/doiLanding?doi=10.1037%2Fxan0000118