This study examines the longitudinal changes in body composition, fat distribution, and energy balance in perimenopausal women over a 4-year period. The primary hypothesis was that total fat and abdominal fat would increase at menopause due to decreased energy expenditure (EE) and declining estrogen levels, respectively. The study included 103 Caucasian and 53 African-American women who were initially premenopausal. Key findings include: 1. **Body Fat and Weight**: Significant increases in body fat and weight were observed only in women who became postmenopausal by year 4. 2. **Abdominal Fat**: All women gained subcutaneous abdominal fat (SAT), but only those who became postmenopausal showed a significant increase in visceral abdominal fat (VAT). 3. **Hormonal Changes**: Postmenopausal women exhibited a significant decrease in serum estradiol and an increase in follicle-stimulating hormone (FSH). 4. **Physical Activity**: Physical activity decreased significantly 2 years before menopause and remained low. 5. **Dietary Intake**: Dietary energy, protein, carbohydrate, and fiber intake were significantly higher 3-4 years before menopause compared to menopause onset. 6. **Energy Expenditure**: Twenty-four-hour EE and sleeping EE decreased significantly with age, but the decrease in sleeping EE was more pronounced in postmenopausal women. 7. **Fat Oxidation**: Fat oxidation decreased by 32% in postmenopausal women, while it did not change in premenopausal women. The study concludes that menopause is associated with an increase in total body fat and VAT, decreased EE, and fat oxidation, which can predispose women to obesity if lifestyle changes are not made. These findings highlight the importance of focusing on the early perimenopausal years to prevent weight and visceral fat gain.This study examines the longitudinal changes in body composition, fat distribution, and energy balance in perimenopausal women over a 4-year period. The primary hypothesis was that total fat and abdominal fat would increase at menopause due to decreased energy expenditure (EE) and declining estrogen levels, respectively. The study included 103 Caucasian and 53 African-American women who were initially premenopausal. Key findings include: 1. **Body Fat and Weight**: Significant increases in body fat and weight were observed only in women who became postmenopausal by year 4. 2. **Abdominal Fat**: All women gained subcutaneous abdominal fat (SAT), but only those who became postmenopausal showed a significant increase in visceral abdominal fat (VAT). 3. **Hormonal Changes**: Postmenopausal women exhibited a significant decrease in serum estradiol and an increase in follicle-stimulating hormone (FSH). 4. **Physical Activity**: Physical activity decreased significantly 2 years before menopause and remained low. 5. **Dietary Intake**: Dietary energy, protein, carbohydrate, and fiber intake were significantly higher 3-4 years before menopause compared to menopause onset. 6. **Energy Expenditure**: Twenty-four-hour EE and sleeping EE decreased significantly with age, but the decrease in sleeping EE was more pronounced in postmenopausal women. 7. **Fat Oxidation**: Fat oxidation decreased by 32% in postmenopausal women, while it did not change in premenopausal women. The study concludes that menopause is associated with an increase in total body fat and VAT, decreased EE, and fat oxidation, which can predispose women to obesity if lifestyle changes are not made. These findings highlight the importance of focusing on the early perimenopausal years to prevent weight and visceral fat gain.