From a few days to a couple of weeks: smoothies, and raw and cooked soups with mung bean soup or kitchdi for supper (see below.) Lots of lemon juice and herbal teas and greens drinks, maybe even some veggie juices if you have a juicer. Caution, this program WILL result in weight loss and, if greatly reduced calories are consumed, can lower the speed of your metabolism if followed for more than a few days, thus potentially leading to weight gain in the future.
The Ayurvedic approach is to combine mung beans and basmatic rice with veggies at every meal and snack for two to three full days. I'll add a post after this with a recipe in the recipe section for Kitchdi. This one is the easiest as there will be very little hunger and you may not lose any weight. Healthy plant based, cold pressed oils can be added to increase calories if needed.
A few days of vegetables only, cooked and raw and soups- plus healthy dressings, sauces etc. You may find this reset option fairly challenging due to hunger. Eating extra helpings of pureed veggies and using some squash and sweet potatoes can help. This option will very likely also result in weight loss and the same cautions apply as in number one.
Go back to your normal phase of the Whole Approach diet but start each day with a veggie juice high in green veggies or with powdered greens stirred in. This will also result in very little hunger as you are just adding juice to what you were eating before the holidays. The juice does a nutritional 'reset' and helps rejuvenate the wisdom of your body to help shift your intuition back to healthy.