Can I use One Meal as a snack?

You can use One Meal whenever it fits in to your daily routine, but you should be aware that
One Meal is designed to replace one or two of your daily main meals, and secures you all the nutrition needed in a main meal for only approx. 200 kcal.

In connection with diet, however, it is important to think about your daily calorie intake, and such you should be aware that adding One Meal as a snack or in-between meal, you will add approx. 200 kcal. to your daily calorie intake.