Overview: Women tend to put on weight after they get married, for reasons that may not seem obvious. Happily married women in the United States gain an average of 37 lbs. in the first decade of marriage, while those in unhappy marriages gain 54 lbs., according to Richard B. Stuart writing in "Psychology Today." Marriage also links to added weight in Australia and an increased risk of obesity in African-American women, according to a pair of studies published in 2010. Misconceptions Extra pounds may be a solution to problems that marriage poses to wives, according to Stuart, who surveyed 25,000 U.S. wives on their weight gain for the book "Weight, Sex and Marriage," written with Barbara Jacobsen. The added weight may serve a useful role for the married woman. Theories Stuart and Jacobson write that a woman's weight and body image are in delicate balance with her marital happiness, sexual satisfaction and self-esteem. Married women surveyed cited a lack of adult companionship if they had left an office to care for a child, fatigue from child and elder care and work, and criticism from their husbands about their increasing weight as reasons they turned to food for consolation. Other stay-at-home mothers said not having daily contact with men diminished their motivation to look their best. Demographics A report published in "The American Journal of Preventive Medicine" in 2010 studied 6,458 Australian women. Annette J. Dobson, a professor of biostatistics at the University of Queensland, found that the 10-year weight gain for an average 140-lb. woman was 11 lbs. if she was childless with no partner, 15 lbs. if she had a partner but not a child and 20 lbs. if she had a baby and a partner. All the women gained weight steadily over the decade of the study. Sociologist Emily Fitzgibbons Shafer of Stanford University found that marriage links to increased BMI for men and women of all ethnic groups and leads to an increased likelihood of obesity for African-American women. Significance Since having a partner is not likely to cause metabolic changes, the weight gain found by Dobson appears to be caused by altered behavior or a metabolic adjustment linked to pregnancy, the New York Times reported. Dobson told the Times that women's bodies may adjust to the increased weight linked to having a baby. Expert Insight Penny Gordon-Larsen, an assistant professor of nutrition at the University of North Carolina-Chapel Hill, notes that single young adults who are dating may have "more incentive to be thin" in an interview with USA Today. In a study released at a 2007 meeting of the Obesity Society, she found that married men and women in their early 20s gained 6 to 9 lbs. more than single peers. Benefits Married women surveyed by Stuart and Jacobson also saw advantages to being overweight. Wives noted that extra weight deflected flirtatious male attention; women who lost weight described being troubled by a temptation to yield to affairs. Women reported disappointing or frightening sexual experiences they attributed to their weight loss. Other women stayed overweight to shelter themselves from fear of failure, where more might be expected of them if they presented a confident, weight-appropriate appearance.