Scientists have discovered that unhealthy snacks after a nutritious meal negates its benefits.

A quarter of the participants in the King's College London study ate unhealthy snacks between their nutritious meals.

Despite choosing healthy options for main meals, bad snacks left participants hungry and with poorer health markers.

Picking at sweet treats, crisps and cakes are linked with a higher risk of obesity, strokes and cardiovascular disease.

The worst time to snack was after 9pm - it was associated with poorer blood markers, plus late night snackers often gravitated towards energy-dense and high fat foods.

The analysis revealed 95 per cent of the participants got through 2.28 snacks a day, with 47 per cent eating two snacks a day and 29 per cent eating more.

Scientists decided that snacking isn't bad for you, provided the food was healthy.

Dr Sarah Berry from King's College London said: "Considering 95 per cent of us snack, and that nearly a quarter of our calories come from snacks, swapping unhealthy snacks such as cookies, crisps and cakes to healthy snacks like fruit and nuts is a really simple way to improve your health."

People who drifted towards nuts and fresh fruits were more likely to be a healthy weight versus those who didn't snack at all, or those who snack on unhealthy foods.

According to the study published in the European Journal of Nutrition, the most popular snacks were cookies, fruits, nuts and seeds, cheese and butter, cakes and pies, and granola or cereal bars.

Cakes and pies had the highest calorie count, adding 14 per cent to the daily intake.

Breakfast cereals followed with 13 per cent, ice cream and frozen dairy desserts popped on 12 per cent, doughnuts and pastries 12 per cent.

Sweets stuck on an extra 11 per cent, cookies and brownies took up 11 per cent and nuts and seeds 11 per cent.

The healthy options could improve the metabolism and decrease hunger.

Dr Kate Bermingham from King's College London said: "This study contributes to the existing literature that food quality is the driving factor in positive health outcomes from food.

"Making sure we eat a balanced diet of fruit, vegetables, protein and legumes is the best way to improve your health."