Done it. Have a healthy 8 year old who is excelling across the board and growing as expected.
And that's completely true BTW, but just adding a gentle reminder that people can say anything behind the Internet.
I'm happy to answer any specific questions or worries.
Fwiw, people will worry bevause its alien to them but probably won't say anything to your face.
I never lied to medical professionals (who incidentally never cast judgement but whom we've rarely had to visit thankfully) but if I sensed it would be awkward with e.g. cousin Pat, I used to fudge it and say she had a dairy intolerance and we're all vegetarian anyway so we're following a vegan diet for simplicity.
But it's honestly been fine.
We do a lot of porridge with flax, chia, nuts, peanut butter. Avocados everywhere. Lentils, chickpeas, stir fry with tofu. Vegan breakfasts are good. Mine happily ate: avocado, toast, baked beans, spinach, tofu and tomato for brunch yesterday. She eats loads of salad as well. Just make sure you're offering loads of fat.
Mine love tofu Whip mousse (basically silk tofu whipped with melted dark chocolate. Yoghurt and fruit is your friend. Tesco yoghurt is the best in terms of lower upf. Plenish milk as well.
Like I said, ask me if you need any info x