Taking breaks during the day and eating food which is rich in protein are good ways to avoid weight gain at work, according to an expert in nutrition.

Helen Heap, nutritional therapist at the Dr Marilyn Glenville Clinic, was commenting following research from the University of Montreal, which revealed a link between an increase in office jobs and rising obesity rates.

Ms Heap said: "Making sure [you take] designated breaks ... will stimulate metabolism and the digestive system. A good lunch would be ... protein rich with beans, tofu or chicken."

She suggested eating food with a low glycaemic index, which she said leaves a person feeling fuller for longer and will make them less likely to snack on unhealthy sugary treats.

Desk-based employees are going to be at risk from gaining weight as they work long hours in sedentary jobs and eat unhealthy "quick fix foods" to give them energy, she said.

Vitamin company Nutrilite undertook a study which revealed that only about one third of women in the US are consuming the recommended daily amount of fruit and vegetables.