Does a low-fat diet slow skin ageing or make it worse?
There is no evidence that a low-fat diet slows skin ageing. It is better to opt for a varied dietary pattern rich in vegetables, fruit, antioxidants and a low glycaemic index, as that overall pattern has the most support for healthy skin.
What the available studies actually say is more nuanced than a simple 'low-fat is better'. The negative link that exists concerns high-fat dietary patterns, not a low fat content as a protective factor. Narrative reviews connect a high-fat diet to more signs of ageing, poorer skin repair capacity and greater damage. But these are associations, not proven cause and effect, and no controlled experiments in humans have been conducted that firmly demonstrate this.
A low-fat diet has simply not been studied in the available sources as an intervention against skin ageing. There are no direct data on what happens to the skin when fat intake is sharply restricted. You therefore cannot conclude on the basis of this research that eating less fat keeps the skin younger.
What animal research shows: in mice, a high-fat diet stimulated the growth of fat cells in the deeper skin layer and the movement of certain skin cells (fibroblasts). Whether that is beneficial or harmful in the long term for skin ageing in humans is not clear.
What does emerge consistently: the overall dietary pattern matters more than fat content alone. Diets rich in antioxidants, vegetables, fruit, nuts and legumes are linked in multiple reviews to healthier skin and fewer visible signs of ageing. It is the combination of a low glycaemic index, micronutrients and hydration that is relevant, not reducing fat as such.
All sources are narrative reviews or animal studies. No randomised controlled trials in humans were found that directly compare low-fat versus high-fat diets on skin ageing outcomes. Causal claims are therefore not justified.