Have you ever forgotten a name or misplaced your keys?

As people enter their 40s, it’s common to notice these little changes in memory or focus.

While getting older naturally affects how our brains work, what we eat plays an important role in keeping our minds sharp.

A study by Harvard found that sticking to a healthy diet in midlife could increase your chance of achieving healthy ageing. 

The research, based on data from over 100 000 people spanning 30 years, revealed that people who followed a healthy diet from their 40s onward were 43-84% more likely to be well-functioning physically and mentally at age 70 compared with those who did not.

In terms of particular foods, the researchers found that higher intakes of fruits, vegetables, whole grains, unsaturated fats, nuts, legumes and low-fat dairy were associated with greater odds of healthy ageing, while higher intakes of trans fat, sodium, total meats, red and processed meats were associated with a lower odds of healthy ageing.

“The brain is incredibly sensitive to what we feed it, especially as we get older,” shares Lev Fomchenkov, CEO of Cosmic Nootropic.

After turning 40, our bodies struggle more to fight inflammation and stress, meaning that unhealthy foods can harm our mental clarity even more.

Here are five everyday foods that could be hurting your brain:

Processed meats: Foods like hot dogs, bacon and sausages are convenient but full of harmful chemicals.

“Processed meats are particularly damaging because they contain advanced glycation end products, or AGEs, which accumulate in brain cells and interfere with normal function,” says Fomchenkov. Regularly eating these foods can speed up cognitive decline.

Swap for: Fresh turkey, grilled chicken or plant-based proteins like lentils and chickpeas. 

Fried foods: French fries and doughnuts are popular, but frying creates harmful compounds that damage your brain. “Think of fried foods as rust for your brain,” warns Fomchenkov. Regularly eating these can lead to memory problems and may increase the risk of dementia.

Swap for: Baked sweet potato wedges or air-fried vegetables.

Sugary snacks and sodas: That candy bar or soda may give a quick lift, but too much sugar can cause problems. “Sugar creates inflammation and interferes with the brain’s ability to form new memories,” explains Fomchenkov.

Swap for: Berries with Greek yoghurt or herbal tea with a bit of honey.

Refined carbohydrates: White bread and pastries can be filling, but they behave like sugar in your body. This can lead to blood sugar spikes, which cause brain fog.

Swap for: Quinoa, brown rice or whole grain bread.

Excessive Alcohol: While a little alcohol can be okay, too much can hurt your brain. It disrupts sleep, which is essential for memory. “What used to be fine in your 20s and 30s can now interfere with cognitive function,” says Fomchenkov.