Replacing Meat & Dairy with A Low-Fat Vegan Diet Can Reduce Postmenopausal Hot Flashes by 92%

A plant-based diet low in fat can reduce hot flashes and weight in postmenopausal women much more effectively than animal proteins.

Replacing meat, dairy and eggs with plant-based foods – regardless of whether they’re classed as healthy or unhealthy – leads to better health outcomes for postmenopausal women.

Hot flashes and weight gain are among the most common symptoms of the postmenopause period, but following a vegan diet can drastically reduce these impacts, leading to greater overall health in women, according to a new study by the Physicians Committee for Responsible Medicine (PCRM).

“Simply replacing meat and dairy products with plant-based foods can lead to weight loss and a reduction in hot flashes in postmenopausal women,” said Hana Kahleova, co-author of the study and director of clinical research at PCRM.

Over 80% of people at menopause experience vasomotor symptoms. These include hot flashes, which studies have shown to increase the risk of diabetes, osteoporosis, Alzheimer’s, and cardiovascular diseases. They can also disrupt sleep, negatively affecting women’s overall wellbeing.

Both ‘healthy’ and ‘unhealthy’ vegan diets reduce hot flashes

The research – published in the BMC Women’s Health journal – is a secondary analysis of data from a 2023 PCRM study, where 84 postmenopausal women reporting at least two moderate to severe hot flashes dairy were either asked to follow a low-fat vegan diet featuring soybeans, or continue their usual diet for 12 weeks.

That initial research revealed that low-fat vegan diets reduced the incidence of moderate to severe hot flashes by 88%. This latest paper builds on that to explore the association of plant-based diet index (PDI) scores with changes in hot flashes.

Characterised by positive marks for plant-based foods and negative scores for animal-derived foods, PDI differentiates between the healthfulness of different approaches to plant-based eating, and has been used in many studies.

PDI measures adherence to a vegan diet in general. Meanwhile, healthful PDI (hPDI) comprises the consumption of ‘healthy’ plant-based foods, such as more vegetables, whole grains, nuts, legumes, oils, coffee and tea. On the contrary, unhealthful PDI (uPDI) includes more foods like fruit juice, sugar-sweetened beverages, refined grains, potatoes, and sweets.

The researchers found that participants eating vegan diets saw severe hot flashes reduce by 92%, while those in the control group experienced no significant changes. Similarly, plant-based eaters also lost an average of 3.6kg in body weight, compared to just 0.2kg for those who ate meat, dairy and eggs.

Crucially, all three PDI cores increased in the vegan participants, with both hPDI and uPDI associated with weight loss and a reduction in hot flashes. And these effects remained significant even after accounting for changes in body mass index.

“The main mechanisms responsible for the reduction in hot flashes in our study may include a high fibre and a low fat content of the vegan diet, weight loss, a reduction in markers of inflammation, and an increased consumption of soy isoflavones,” the authors wrote.

Important findings among the ultra-processed discourse

“The good news is that our new analysis helps clarify that even plant-based foods that are defined as ‘unhealthy’ by the plant-based index are better than animal products in terms of weight loss and reduction in hot flashes,” said Kahleova.

The research comes at a time when plant-based meat and dairy products are being bundled with items that happen to be vegan – such as breads, biscuits and cakes – to be falsely discredited as unhealthy ultra-processed foods (UPFs). In reality, the term is used to describe the level of processing, and not a food’s healthfulness.

Nevertheless, the UPF tag has hurt sales and spurred even giants like Beyond Meat and Impossible Foods to rethink their product formulations and marketing strategies.

The PCRM research notes that fruit juices, sweetened beverages, potatoes and refined grains all have higher carbohydrate and lower fat content than meat, dairy and eggs, and so are naturally lower in energy density.

Even though potatoes are viewed as ‘unhealthy’ here, the evidence between these tubers and type 2 diabetes risk is “weak and inconsistent”, and subject to variables like the use of fat during preparation and combination with meat in meals. In fact, potatoes have been found to be comparable to beans in weight loss and improvements in insulin resistance.

“If you want to lose weight, fight hot flashes, or improve other diet-related conditions like type 2 diabetes and heart disease, it’s always best to choose the plant-based option over animal products,” said Kahleova.

The findings echo the results from a 2012 clinical trial of over 17,000 women, which found that increasing whole grains, fruits, and vegetables and reducing dietary fat boosted the chances of becoming free of hot flashes at one year by 14%, regardless of weight changes.