effects of fast food

The effects of fast-food diet can have on your body are widely known, but fast food can also have unexpected negative effects on your mood and mental functioning.

1. Need for instant gratification

In an experiment to check the effect of fast food vulnerability on delaying gratification, students were randomly split into two groups. One was given the task of rating fast food logos and the other rated the logos of local diners. Both groups were then asked to make a series of choices between receiving $3.00 immediately or an amount ranging from $3.05 to $7.00 one week later. The students who viewed the fast food logos required higher future amounts to convince them to give up the instant $3.00. The researchers concluded that exposure to fast-food symbols led people to prefer immediate gain over greater future return.

2. Drive to Eat Faster and Overeat

The atmosphere of fast-food restaurants is designed to encourage people to eat quickly and leave. Bright lights, loud music, and a red and yellow color-theme make it hard to relax. In a study to examine whether changing the restaurant atmosphere would affect the amount of food consumed, researchers divided a Hardee’s restaurant into two sections. Study participants were randomly selected to eat in the fast-food section or one made over as a fine-dining restaurant with dim lighting and soft jazz. Even though participants in the fine-dining area lingered longer, they ate an average of 200 fewer calories than those in the fast-food atmosphere.

3. Feeling rushed

In a study examining fast food and impatience, students were asked to type a short paragraph on a computer and then keep their focus in the center of the screen while images flashed in the corners. Half of the students were exposed to images containing hidden logos of fast-food restaurants that appeared too briefly to reach consciousness. Researchers then measured the time it took the students to read a passage. Students who viewed the fast-food logos were 15 seconds faster on average. The researchers theorized that exposure to fast-food symbols triggers impatience which automatically increases reading speed even when people are not under time pressure.

4. Less enjoyment

A survey of people throughout the US asked respondents about their ability to savor pleasurable activities such as discovering a beautiful waterfall on a hike. The researchers then used the participants’ zip codes to determine the concentration of fast-food restaurants in their neighborhoods. They found that people living in areas with the most fast-food outlets got less enjoyment out of experiences that required them to ‘stop and smell the roses’. The results remained significant even after controlling for economic factors. Because fast food is associated with impatience, it may also diminish the ability to slow down and savor life’s simpler joys.

5. Depression

A Spanish study following 9000 university graduates found an association between fast food consumption and depression. None of the chosen participants had been diagnosed as depressed. They all completed a food frequency questionnaire which asked about consumption of fast food including hamburgers, sausages, and pizza. The graduates were followed up for a median of 6.2 years. Over this time a total of 493 cases of clinical depression were reported. Analysis of the data showed that people who ate the most fast food had a 37% greater risk of developing depression than those who ate the least.

6. Addiction

A study on rats found that the same brain mechanisms that cause drug addiction are behind the compulsion to overeat. The scientists allowed a group of rodents to gorge on high-calorie, high-fat foods for 40 days. They took in twice as many calories as a control group and became obese. The fat rats became fast-food addicts. They continued to overeat even when they anticipated receiving electrical shocks. When the high-calorie food was removed and the animals were given the ‘salad bar option’, they refused to eat. The obese rats’ brains showed a reduction in levels of the D2 dopamine receptors. The very same change occurs in the brains of rats fed cocaine or heroin.

7. Fatigue

A study on rats showed that a fast-food diet could lead to lethargy and fatigue. Half of the rodents were fed a healthy diet. The other half were given a processed diet, higher in sugar, and lower in nutrition. After three months, the rats on the fast-food regime became obese, while the control group did not. The animals were tested on a task that required them to press a lever to receive a reward. During a 30 minute session, the rats on the unhealthy diet took breaks that were nearly twice as long as those taken by rats on a healthy diet. Researchers concluded that either the highly processed diet causes fatigue or the diet causes obesity, which causes fatigue.

8. Alzheimer’s

A Swedish study showed how fast food may play a role in the development of Alzheimer’s disease. Researchers used mice genetically modified to mimic the effects of a gene variant that puts humans at greater risk for Alzheimer’s. The mice were fed on a diet with a nutritional content typical of fast food, including high levels of sugar, fat, and cholesterol. After nine months, the brains of the mice were examined. They showed chemical changes that lead to the neurofibrillary tangles seen in the brains of Alzheimer’s patients. The researchers suspect that a high intake of fat and cholesterol, in combination with a genetic predisposition, can contribute to the onset of Alzheimer’s disease.