This study tests the hypothesis that a low-fat, vegan diet including soybeans reduces the frequency and severity of menopausal hot flashes, and tests the hypothesis that total isoflavone intake is associated with the reduction in the frequency and severity of hot flashes.

Women with postmenopausal hot flashes will be recruited via social media and randomly assigned to an intervention or control group. The intervention group will be asked to consume a low-fat, vegan diet including ½ cup (86g) cooked soybeans (30 g uncooked) for 12 weeks. Support will be provided by weekly meetings conducted via an Internet video conferencing platform (e.g., Zoom), along with individual counseling as needed. The control group will be asked to make no diet changes for 12 weeks but will be offered instruction in how to follow a vegan diet and about the potential role of soybeans after the 12-week point. The frequency and severity of hot flashes will be assessed before, during, and after the 12-week intervention.

Inclusion Criteria:

1. Post-menopausal women aged 40-60 years
2. English fluency
3. Moderate-to-severe hot flashes experienced at least twice per day
4. Started menopause within the last 10 years
5. No menses in preceding 12 months
6. Access to an iPhone or Android phone and willingness to install a hot-flash recording app.
7. Willingness to participate in weekly classes
8. Willingness to follow a low-fat vegan diet, including daily consumption of soybeans.

Exclusion Criteria:

1. Use of hormonal medications in the preceding 2 months
2. An explanation for hot flashes other than menopause (e.g., medication use, cancer treatment)
3. Smoking during the past six months
4. History of an eating disorder or evidence of a current eating disorder (as determined by an eating disorder diagnosis, the discretion of a qualified medical professional, or an Eating Attitudes Test-26 score >20)
5. Alcohol consumption of more than 2 drinks per day or the equivalent, episodic increased drinking (e.g., more than 2 drinks per day on weekends), or a history of alcohol abuse or dependency followed by any current use
6. Use of recreational drugs in the past 6 months
7. Use of weight-loss medications over the last 6 months or a current attempt to lose weight
8. Body Mass Index < 18.5 kg/m2
9. Soy allergy

This study only seeks people who have had their last period, thus excluding males.

The control group will be asked to stay on their usual diet.