I can't recall a time when Miss E hasn't been pestering me for a glass of juice. Even at nearly 10 years of age it is her drink of choice. No fizzy pop for her, she just isn't interested but 100% pure unsweetened juice or maybe a homemade smoothie and she is as happy as Larry (whoever he is!).
She affectionately calls OJ her 'brain juice' and insists on having a glass of it at breakfast as one of her recommended 5-a-day. I've always been happy with this as combined with a bowl of porridge or weetabix and milk it is a healthy breakfast that helps her stay full and focused on learning until her break time at school.
Research (1) shows that only 8% of 11-18 year olds achieve their minimum 5-a-day consumption of fruit and vegetables, so a small glass (150ml) of pure juice is a nice easy way to fill one of those five slots and perfectly I've found that 150ml fits in the empty Nutella glass nicely and makes it easy for Miss E to be able to measure out her own drink in the morning.