There are many reasons for skin aging, some of which are related to personal fitness, and some are caused by external factors. Irregular eating habits can lead to obesity or underweight, and it is more likely to cause the two situations to alternate. In addition, various combinations of the body's components, Uneven distribution of carbohydrates, oils, proteins, vitamins and essential trace elements in the body can also cause skin aging. What does this text want to express? ['Uneven distribution of trace elements.', 'Obesity or underweight is related to personal fitness.', 'Causes of skin aging.', 'Irregular eating habits can cause obesity or underweight.']