However, while overnight oats may be soaring in popularity across the nation, not all may be quite as healthy as it initially seems. Indeed, according to Kieran Jenkins, a nutritionist at Supply Life, while overnight oats may hold a 'strong health halo, the name alone tells us very little'. M&S Overnight Oats with Apple and Cinnamon 70gIngredients: Oat flakes (65%), concentrated milk protein, dried skimmed milk, ground dates, dried apple pieces (7%), sweet cinnamon (cassia). It is more processed than a basic oat-and-fruit mix because of the added milk protein, but that addition serves a useful nutritional purpose. A product can contain oats, seeds and fruit while still delivering a surprisingly large sugar hit.