Alcohol
In excess, alcohol can interfere with the quality of your sleep. Stick to safe limits and have one or two alcohol-free days a week.
Smoking
Nicotine stimulates the brains initially, but then acts as a depressant. Smoking also increases the rate at which the liver uses up microntrients, especially the B vitamins and vitamin C. It also makes extra work for the antioxidants that help to detoxify the body.
Anxiety And Stress
Make a habit of doing something everyday that takes your mind off the problems, whether it is exercise, meditation, listening to music or gardening. Do it until you feel relaxed.
Allergies
Fatigue can be the only sympton of intolerance or allergy to particular foods, which may be worth considering as the cause of unexplained lethargy.