Seven foods that will impact your intelligence ... but not in a good way. Foods that will make you less smart. IF YOU chow down dark chocolate before a big all-nighter, and fill your plate with leafy greens, fish and nuts, congratulations. You're a smart eater, because those foods have been proven to sharpen your thinking ability. But before you leap with joy and submit your application to Harvard or Cambridge, read this, because you're probably eating foods that will make you less smart as well, reports Life Hack. And not only do these foods make you 'dumber', they diminish all your efforts to be smart, and effectively undo all your 'smart eating'. You've probably heard that sugar is bad for you. It's bad for your teeth, your liver and makes you put on weight. Naturally occurring sugars in fruit are fine when consumed in proportion, but high-fructose corn syrup used in most confectionary and soft drinks is the big culprit. But maybe you haven't heard that when sugar is consumed in large amounts (think a whole packet of lollies) over an extended period of time, it alters your brain's ability to learn and remember information. So eating your way through a packet of jelly beans while writing a 3000 word essay is not a good idea. Try to limit your sugar intake, and snack on foods like nuts and fruit instead. Over-consumption of sugar can lead to a decrease in your brain's activity. It's one of the best flavours ever created, especially when found in bacon and other cured meats, chips and our all-time-favourite: Vegemite. But aside from affecting your heart rate and blood pressure, salt also affects your cognitive functioning. In 2011, scientists found that eating a high-salt diet was strongly linked with a faster cognitive decline in elderly people. Adding raw salt to your food is worse than cooking with salt, so when you do eat it make sure it's cooked in your meal. The picture says it all. This one is a surprise, being often regarded as a healthy food. However research from Loughborough University and Oxford suggests that tofu can be harmful if consumed in large quantities. The two universities conducted a study with 700 participants between the ages of 52 and 98. The results show that those who consumed a lot of tofu were more at risk for memory loss. The quiet memory-killer. Delicious yet perilously addictive, junk food is a big one to avoid. Life Hack reports that the practice of eating junk food has been shown to trigger symptoms similar to withdrawal, depression and anxiety. And from there it's often a dark spiral downward as depressive symptoms often prompt a desire to eat junk food, and so on. Studies show that fat and sugar-laden foods appear to reduce levels of a natural brain chemical that is crucial for learning. In essence, junk food is rotting away your memory capacity. Would you like anxiety, memory loss or depression with that burger? Why is it that the worst possible foods taste so good? Everyone knows that chicken tastes amazing when it's deep fried, and battered fish trumps fried fish. But the oils and trans fats in these foods are killing our brains, literally. A recent study has further confirmed this fact stating that "people who had high levels of circulating trans fats had less brain volume. They also had poorer memory, attention, language and processing speed skills. Fried food also clogs the arteries, and can cause heart attacks and aneurysms. So in short, stay away from the fried, fatty stuff. Why oh why does it taste so good? It's a well known brain depressant, causing difficulty walking, blurred vision, slurred speech, slowed reaction times and impaired memory in the short term. But studies show that alcohol can have long term effects. A person who drinks heavily over a long period of time may have memory deficits that persist long after they regain sobriety. The effects of heavy and long-term drinking on the brain are blackouts, memory lapses and serious brain disorders like Wernicke - Korsakoff Syndrome. Doctors recommend you limit your consumption of alcohol to 1-2 glasses per week. Don't let it get to this. They're everywhere, and often in disguise. Processed foods contain a deadly cocktail of harmful ingredients like preservatives, additives, dyes and artificial flavours, all of which affect your brain function. Science has shown that high-fat processed foods cause damage to the hypothalamus in the brain - the area responsible for monitoring and signalling levels of hunger, thirst and the body's natural rhythms and cycles. So steer clear of these, no matter how yummy they look. They're hard to avoid, particularly around Christmas time. Which foods will you be cutting out of your diet?