The candy bars in the hotel room mini-bar. The glazed pastries at the free breakfast buffet.
And, finally, the biggest hurdle to keeping fit and eating healthily while travelling - the kiosk at the airport, with its array of food guaranteed to test the takeoff ability of the most powerful jet.
So how do you eat well and stay trim while living out of a suitcase?
The answer comes down to one word, doctors and other health experts say: preparation.
Here are 10 tips to help you avoid returning from your next trip with extra baggage around the waist.
1. Make time to exercise at least as often as you do at home.
2. Pack your running shoes and workout clothes.
You will then feel too guilty not to exercise.
3. Plan to see as much as you can by foot. Walking not only burns kilojoules but also saves money on transportation.
4. Refuse the key to the in-room mini-bar, if there is one, which will save you money (do you really want to pay $2.50 for a bag of chips?) and eliminate the temptation to snack.
5. Pack yourself a few healthful snacks so you don't eat the less healthy preheated stuff served on aeroplanes and in hotel bars.
6. Once you clear airport security, buy a bottle of drinking water to keep you hydrated during the flight and help you fight the temptation to suck down those high-calorie soft drinks.
7. If your hotel offers a free continental breakfast, skip the glazed pastries. Try yoghurt or whole-wheat cereal with low-fat milk.
8. If you are going to be on the move all day - say, taking your kids to an amusement park - try to have at least one healthy sit-down meal. A solid meal will reduce your chances of snacking throughout the day.
9. Drink alcohol in moderation - it's loaded with calories.
10. Be active. If you're holidaying by the shore, don't lie on the beach all day. Take surfing lessons or rent a bicycle to explore the coast. Use your holiday time to play like a kid.
