Veganism is booming among middle class families who claim it is a way to save the planet and boost their health at the same time.
But nutritionists in the UK have now warned parents to think twice before putting their children on a vegan diet.
The British Nutrition Foundation (BNF) said that restricting toddlers to a plant-based diet can risk depriving them of vital vitamins and minerals.
They issued updated nutrition guidelines for toddlers yesterday amid a growing trend for veganism in Britain that has seen companies launch vegan baby food.
The BNF urged caution for parents considering putting their child on a vegan regime, and said they should take them to a GP first to get vitamins and dietary supplements. The guidelines, developed by top nutrition scientists, said toddlers should aim to eat two or three portions of protein foods in order to get enough iron and zinc. This can be difficult as a vegan diet, although the BNF did acknowledge that a 'well-planned' vegan diet could be healthy for young children.
The BNF guide - named the 5532-a-day - recommends children aged one to four eat five daily portions of starchy foods such as bread or pasta, five of fruit and vegetables, three of dairy and two of protein, such as eggs, chickpeas or fish, rising to three if they are vegetarian or vegan.
Sara Stanner, science director at the BNF, said: "Even when parents know which foods are part of a healthy diet, it can sometimes be difficult to know what sized portion is suitable for a young child, and how often they should be eating from the different food groups each day."
She added that sugary treats like "biscuits, chocolate and sweets shouldn't be a regular part of children's diets".
The guide also says that fruit juices can provide some important vitamins, but are high in sugar and are acidic - which can damage young teeth. It advised they should only be consumed at mealtimes and should be diluted.
The number of vegans in Britain - who cut out meat, eggs, dairy and animal products, such as honey - quadrupled between 2014 and 2018 to 600,000, around 1.2 per cent of the population.