For years, women have been sold the same tired protein panic.
Eat more protein.
Prioritise protein.
Get enough protein.
And, somewhere underneath all of that, the same assumption keeps appearing: animal protein is the gold standard.
A new study suggests something very different. Researchers looking at postmenopausal women found that replacing animal protein with plant protein was linked to significant weight loss, even when total protein intake stayed roughly the same.
The women were not simply eating less protein. They were changing where that protein came from. Animal protein went down. Plant protein went up. Body weight fell.
In the low-fat plant-based group, animal protein intake dropped by 23.3g per day, while plant protein rose by 22.1g per day. Total protein barely changed. Yet body weight fell by 3.6kg, compared with just 0.2kg in the control group. So perhaps the question was never just “how much protein?” Perhaps it was always “what kind?”
The researchers found that each 1kg of weight loss was associated with a reduction of 16.2g of animal protein per day and an increase of 12.7g of plant protein. The effect was independent of energy intake.
Animal products bring more than protein. They bring cholesterol, saturated fat, and a different amino acid profile. The study points to methionine, an amino acid found in higher concentrations in animal products, as one possible piece of the picture. Lower methionine intake was associated with lower BMI. This does not mean one nutrient explains everything.
It means the usual “protein is protein” line is too crude.
A trial found something else too. Moderate-to-severe hot flashes fell by 88% in the group eating a low-fat plant-based diet with daily soybeans. Half of the women who completed the intervention had no moderate-to-severe hot flashes at all by week 12. Less animal fat. More fibre. More soy. More plant protein. Fewer animal products.
The findings do not prove every individual will get the same result. The study was short, the group was small, and the intervention combined several changes.
But it does challenge a very profitable myth. Animal protein is not special. It is not even helpful.