1. Take a suitcase full of shakes and don't allow a morsel of food pass your lips.
2. Count calories. Allow yourself to eat maybe 1500 calories a day. This is a good option if you think you're going to want to drink (but remember to count the calories in those drinks too )
3. Eat low carb. No bread, chips, pasta, rice - just lots of protein and vegetables. This has the benefit at least of keeping you in ketosis so will keep the munchies at bay. Remember too that low carbing puts bacon and egg back on the menu.
4. Eat whatever you want. Ironically, giving yourself permission to do this will often lead to you eating less than you might have done had you gone thinking you'd stick to shakes then fall off the wagon before you get to the airport. The key is that 'permission' word.
In fact, the key to any of this is in the planning. Make a decision - and be honest with yourself about which one you're most likely to manage - and then (most important this bit) - STICK TO YOUR DECISION LIKE GLUE.
You're likely to do most damage if you end up trying to do a haphazard combination of all of the options - so pick one now and plan what sort of things you're likely to eat - then concentrate on thinking of things that you'll do that don't involve eating. Remember that extra activity also burns calories, so plan in lots of things that don't mean you'll be tempted to chain yourself to a sunbed for the week.
Hope you have a fantastic holiday, whatever you decide!