Reset digestion and metabolism

During the first five days, you’ll sip three enzyme-rich, protein-boosted smoothies to nourish and heal the liver and pancreas and kick fat burning into high gear, says celebrity trainer Harley Pasternak, who outlines the plan in

The Body Reset Diet (Rodale, 2014; Paperback $16, Kindle $10, Nook $11).

For best results, opt for a whey protein powder that contains at least 15 grams of muscle-building protein per serving. Nutritionist Anne Louise Gittleman, Ph.D., recommends undenatured whey protein, which is specially formulated to be highly absorbable and easy to digest without fat-packing chemical additives. One we like: Reserveage Nutrition Grass-Fed Whey Protein ($24 for 12 servings,

The Vitamin Shoppe stores). If dairy doesn’t agree with you, Pasternak suggests a pea and rice protein powder, like Purely Inspired Organic Protein ($25 for 19 servings, iHerb.com).

You can also enjoy two snacks each day if you get hungry. “Snacks should be about 150 calories, contain fiber and protein and have less than 5 grams of sugar,” advises Pasternak. Some top picks: 8 oz. of fat-free Greek yogurt with 1⁄3 cup of raspberries; 5 ribs of celery with 1 Tbs. of nut butter; or 4 cups of air-popped popcorn.

Also smart: Add a targeted probiotic. Research from the U.S. Department of Agriculture shows that the probiotic strain Bacillus subtilis supports the production of enzymes to help the body break down protein and alleviate bloat and discomfort. Populating the gut with this super strain for four weeks will allow it to take root, so the beneficial bacteria will keep working for you to help aid digestion for life. A brand that contains the study-backed strain:

Just Thrive ($49 for a 30-day supply, SwansonVitamins.com).