Obesity, especially when fat accumulates in the abdominal region, increases the severity of insulin resistance,10, 11 and has been associated with IRS.12, 13 Loss of excess weight tends to improve insulin sensitivity (i.e., reduce insulin resistance),14, 15 and this has been recently shown to be true for people with IRS as well.16 Weight loss also reduces many of the other health risk factors associated with IRS.17
Cigarette smoking, in most,18, 19 though not all,20 studies, as well as exposure to secondhand smoke21 and use of nicotine replacement products,22, 23 have been associated with insulin resistance. Smoking cessation has been shown to increase insulin sensitivity in healthy people.24
Alcohol consumption in the light to moderate range (up to 1 drink per day for women and up to 2 drinks per day for men25) is associated with better insulin sensitivity in healthy, nondiabetic people.26, 27, 28, 29 Since alcohol consumption also reduces other risk factors for heart disease,30, 31 it does not appear that people with IRS would benefit from avoiding alcohol if they are currently light to moderate drinkers. However, alcohol is potentially addicting and can increase the risk of other diseases, so people with IRS who are not users of alcohol should consult a doctor before starting regular consumption of alcoholic beverages.
Either aerobic exercise or strength training improves insulin sensitivity in both healthy and insulin-resistant people in most studies, 32, 33 though a recent controlled trial found that aerobic exercise alone did not affect insulin resistance in people with IRS.34 Studies comparing strength training to aerobic exercise in insulin-resistant people have reported greater benefits from strength training,35, 36 but a combination of the two will probably be more effective than either one alone. Current recommendations for exercise includes about 30 minutes per day of moderate-intensity aerobic exercise and muscle strengthening exercises (working all major muscle groups) at least two days per week.37, 38, 39 In addition, exercise has many benefits in reducing many of the risk factors associated with IRS.40
Some popular diet books claim that insulin resistance causes weight gain and prevents successful weight loss. However, one controlled study found no difference in the number of women experiencing successful short-term weight loss between women with or without insulin resistance.41
Insulin sensitivity decreases after certain stressful experiences, such as surgery,42 and decreased insulin sensitivity is associated with work-related mental and emotional stress,43 and other aspects of a stressful lifestyle.44 However, these associations have not been explored in people with IRS, nor has stress reduction been investigated as a treatment for IRS.