Nutrition 
Actually, on holiday you have the same nutritional requirements as at home. Therefore, choose healthy foods, be moderate in fat, salt and sugar intake and eat regularly. Try to avoid eating more than normal. Always have a sandwich, biscuit or glucose with you. Drink sufficient water, especially during air travel and when in hot climates (at least 2 litres per day). In some countries, bottled mineral water may be a safer option.

Medication on your journey 
It is often difficult to get the same medication overseas. So, take sufficient for the entire holiday period. Before leaving, check the expiry date of your medications and keep them, as far as possible, in a cool, dark place. Take an extra prescription, just in case.

Because diarrhea can have unpleasant consequences for the water balance in the body, it's a good idea to include Oral Rehydration Salts (ORS) in your luggage. You can buy ORS without a prescription at the drugstore or pharmacy. Ask your doctor what you should do in case of diarrhea or illness. 

Make sure you get your vaccinations early so you will not be caught by surprise during your trip, by unexpected side effects from the vaccinations. 

If you travel abroad, it is wise to take a medical certificate with you, which says that you have diabetes mellitus and that you use tablets and / or insulin. This statement is useful when you suddenly need a doctor or medication. It can also avoid any difficulties at customs.