Mmany of us spend money on treatments and skincare to give us a Meghan Markle-style glow. But what we really should be concentrating on is food and exercise, according the the experts.

Healthy living really does give skin a golden glow, reveals new research by Scottish scientists.

Exercise, avoiding stress and sleeping longer all significantly improve complexion, according to the study published in the journal Frontiers in Psychology.

A diet full of fruit and vegetables also made the skin look healthier and more attractive.

Researchers at the University of St Andrews measured the fitness of 134 students by taking their heart rate while walking and running on a treadmill.

They assessed body fat levels with an impedance meter - much like that available on bathroom weighing scales.

Skin colour was measured with a device that records how a rainbow of colours is reflected from the skin.

Results showed both high fitness and low body fat were associated with an increased skin yellowness - or a "golden glow". This was unrelated to a better diet or a suntan from being outdoors.

Scientists say the colour change is due to the accumulation of coloured plant pigments in the skin, such as orange carotene from carrots and red lycopene from tomatoes.

These pigments, called carotenoids, play an important role as antioxidants and protect against damage caused by everyday stresses and strains.

Exercise boosts the body's own antioxidant systems which may spare the carotenoid pigments so they can accumulate in the skin.

Losing excess body fat, reducing mental stress and better quality, longer sleep, may decrease the production of oxidative toxins.

Skin yellowness could be an indicator of a person's health by demonstrating the body has enough reserves and low oxidative toxin levels.

The research team then assessed whether a change in health altered skin appearance.

They followed 59 students from sports clubs and measured the impact their training had on their overall skin appearance over eight weeks.

Those that increased in fitness or lost body fat showed an increase in skin yellowness.

Questionnaires showed increased psychological stress and a loss of sleep were also associated with a reduction in skin yellowness.

Skin colour change was not due to training outdoors or suntan.

Study leader Professor David Perrett said: "As people get healthier, others should be able to notice the improvement in skin colour.

"We were surprised to find that the skin colour changes accompanying change in health occurred quite quickly and within eight weeks.

"This means that any effort to improve lifestyle will benefit appearance within a relatively short time.

"Given the effect of skin colour on attractiveness, the research findings may help motivate people to follow healthier lifestyles such as exercising frequently, avoiding excess calorie intake and undue stress and adopting good sleep habits.

"All these lifestyle factors, in addition to eating more fruit and vegetables, induce an attractive golden glow to the skin."