1. cause
1.1. Junk food is delicious and addictive
1.1.1. Gong Xionghui, chief physician of Endocrinology Department of Shougang Hospital of Peking University, said that the process of high-fat diet "manipulating" the brain is not controlled by us. The central nervous system of the brain plays an important role in energy and glucose metabolism.
1.1.1.1. When people eat junk food, the hypothalamus and microglia are activated, which can further activate the appetite control neurons in the brain and make people want to eat more high-fat food. In this way, it will enter a vicious circle, which is why the high-fat diet tastes especially delicious.
1.1.1.1.1. https://www.cell.com/cell-metabolism/fulltext/S1550-4131(19)30439-5
1.2. It's related to people's living habits.
1.2.1. Today's society pursues a fast-paced lifestyle, so convenient and fast junk food has become people's first choice
1.2.1.1. Eating junk food can be a way for people to relax
2. effect
2.1. Cause physical health problems
2.1.1. Eating junk food for a long time can lead to obesity, lack of absorption of vegetables, and even a large number of fried food can cause cancer
2.2. Cause mental health problems
2.2.1. Obesity is generally associated with high intake of junk foods rich in energy, fat, sugar and salt combined with a dysfunctional control of appetite and lack of exercise.
2.2.1.1. https://www-cambridge-org.ucc.idm.oclc.org/core/journals/british-journal-of-nutrition/article/maternal-junk-food-diet-in-pregnancy-and-lactation-promotes-an-exacerbated-taste-for-junk-food-and-a-greater-propensity-for-obesity-in-rat-offspring/3D1F88C4A06FAF92FDDB4F28E364E439
2.2.2. Children eating a diet high in ‘junk food’ in early childhood were more likely to be in the top 33% on the SDQ hyperactivity sub-scale at age 7.
2.2.2.1. https://www.nature.com/articles/1602967