Technical Paper 1:
Obesity in Australia: a need for urgent action
2.4 - Trends in weight gain by age
Some age groups have gained weight at a faster rate than others, showing a trend towards earlier weight gain at younger ages. Between 1995 and 2004–2005, the greatest increase in the prevalence of obesity was observed for:
- Adults 25–44 (up 6.1%)
- Adults 45–64 (up 6.1%) (Fig. 4).
Figure 4: Percentage of obese persons by age group: 1995 vs 2004–200555
Source: Unpublished DoHA analysis (2008) of 1995 and 2004–2005 National Health Survey data
As illustrated in Figure 5A & B (over), the mean BMI of young adults is increasing compared with previous generations.[27, 28] In addition, younger generations are gaining weight faster than previous generations. On current trends, Generation X males – those born from the mid-1960s to late 1970s – will have the highest mean BMI of any generation (Fig. 5A). Similarly, while baby-boomer generation women (Fig. 5B) are predicted to have the highest average BMI in 2010, younger women (Generation X) are gaining weight faster than other generations of women.
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Overweight Generation Xers are now the parents of young children, placing these children also at risk. With the rapid increase in BMI in younger women (Generation X and Generation Y), there is mounting concern about the impact of an unhealthy body weight on pregnancy outcomes. Excessive weight gain during pregnancy is directly associated with having an overweight child, and with gestational diabetes, and may lead to weight gain and diabetes in later life in the mother.
Figure 5A
Figure 5B
Figure 5A and B: Mean BMI by birth cohort for men and women in Australia 1990–2000 and 2010 projections
Source: Allman-Farinelli et al 2006 [27, 28]
5The increase observed in 25–44-year-olds may be partly explained by the fact that, between 1989–1990 and 2001, despite relatively low absolute levels of obesity, obesity prevalence in 20–24-year-olds more than doubled from 4.4% to 9.5% (AIHW 2003).