The human body is an excellent system overall. When a human intake harmful food to one’s system, the body understands this and takes precautions. These precautions are basically like storing food and water. When one eat bad food the body doesn’t digest this food in order to avoid being poisoned. Thus body stores food and water for incoming “bad days”. This stored fat is making people fatter and diabolical. (Pietrangelo & Carey & Holland, 2017) Also according to the various articles, the physical and mental damage caused by fast food is proven. One of these experiments was done with mice. Professors aimed to observe if the high-fat diet affect physical and mental capabilities of the rats. Firstly 42 rats were fed with standard fat diet. Their physical activity capabilities were measured by how long they could run on a treadmill and their brain functions or ‘working’ memory was measured by a maze task. 21 of the rats were then taken to fat-based diet so half of the calories have been gained from fat. The new diet has been applied for 4 days, the physical and mental performance of the rats on the normal and fat-based diets was compared for next five days. “With the standard feed, 7.5 percent of the calories come from fat. That’s a pretty low-fat diet, much like humans eating nothing but muesli,” says Dr. Murray.(“High-Fat diet affects physical and memory abilities”,2009) “The fatased diet, in which half of the calories came from fat, seems high but it’s actually not too high by human standards. A diet comprising junk food would come close to that. On the fifth day of the fat based diet (First treadmill test after new diet.), the rats were already running 30 percent less far than their past records. At the last day of the experiment they were running 50 percent less far.(“High-Fat diet affects physical and memory abilities”,2009) The rats on the high-fat diet were also making more mistakes in the maze task, suggesting that their mental abilities were also being affected by their fat-based diet. The number of correct decisions before making a mistake degraded from over six to an average of 5 to 5.5 (“High-Fat diet affects physical and memory abilities”,2009) These experiments also show us that excessive amount of fast-food can kill. Because when storing this bad fats body reaches its limits and makes himself sick in order to get rid of this excessive fats and nutrients.