http://starlite.crchealth.com/what-do-drugs-do-to-your-body/ says Drugs are chemicals that make changes to the make-up of the human body. Some drugs make changes that are necessary, like when someone needs insulin for diabetes or chemotherapy for cancer. Legal drugs are drugs that we use because the good that they do outweighs the possible harm they could do to the body. Illegal drugs are illegal because they have no real benefit other than to make the body feel good, and they might do so much harm to the body that they aren’t worth the risk that comes with taking them. Essentially, http://www.fitday.com/fitness-articles/nutrition/healthy-eating/fast-food-nutrition-junk-foods-effect-on-your-body.html#b says Junk Food hurts the body by affecting your energy. Junk Food makes obese and fat. It damages your arteries and heart, by giving you strokes or heart attacks. It can give you diabetes. It can also give you depression and its addicting. On days that kids ate fast food, compared to days that they ate at home, adolescents and young children consumed an additional 309 and 126 calories, respectively. The study also found that eating at full-service restaurants increased children’s average intake of sugar, total fat, saturated fat and sodium. Based on the current evidence, there is a strong correlation that exists between eating out, consuming more calories and fewer nutrients and an increased risk of childhood obesity and chronic disease. Says http://www.huffingtonpost.com/2012/11/27/fast-food-health-arteries-beauty_n_2198725.html. Exercise is good for body. For example, it reduces the risk of developing heart disease, stroke, high blood pressure, some cancers, type 2 diabetes and osteoporosis. Regular physical activity also helps to control weight, and may help to ease stress. Ideally, you should aim for at least 30 minutes of moderate intensity physical activity on at least five days of the week. Says http://www.patient.co.uk/health/Physical-Activity-For-Health.htm. http://www.bcairquality.ca/health/air-quality-and-health.html says Coughing and wheezing are two of the mild problems associated with inhaling PM2.5. However, this type of air pollution can also cause or worsen serious illnesses such as asthma, heart disease, chronic bronchitis, emphysema and pneumonia. Exposure to PM2.5 is associated with a significant rise in the number of premature deaths from respiratory and heart disease. It's also linked with more emergency room visits, hospitalization, and time off work and school. Long-term exposure in pregnant women can cause premature births and low birth weights. Senior citizens, infants, and people who already have lung, heart and other illnesses (such as diabetes) are the most vulnerable. However, healthy adults and children can be affected, too. PM2.5 and asthma are a bad mix. PM2.5 can increase the number of asthma attacks, and make them more severe. Over 1.2 million Canadians suffer from this condition, and asthma is the most common cause of medical emergencies in children.