I’m sure you know the old saying, “you are what you eat.” Well, it’s true!

Glowing skin, a bright smile, and happy insides are the result when you take care to eat “the good stuff.” My doctor, who is also a great teacher of mine, Dr. Mark Hyman has some simple advice about deciding what to put in your mouth:

The best advice is to avoid foods with health claims on the label, or, better yet, avoid foods with labels in the first place.

This is exactly right. Fresher is better, the less processed the better when it comes to edibles. This is my rule of thumb: if a food’s shelf life is indefinite, you definitely shouldn’t be eating it!

Let’s get real for a minute. You know the foods to avoid at a glance. They have neon colors not found in nature; they crunch with crispy fat or glisten with sugar crystals, and they seem to stay “fresh” forever. They are overly processed, overly sugared, and overly dosed with preservatives.

If you eat like crap, you will feel like crap! Stop right where you are, put your hands up in the air, and drop that block of cheese, loaf of bread, or bag of candy! It’s over.

Start Fresh

The best way to stop feeling like crap is to stop eating it. Just stop. The best way to do this is to keep in mind the old saying “out of sight out of mind.” Toss out the chips and the snacky cakes. Dump those “power” drinks loaded with sugar and caffeine down the drain. I’m not kidding! Go through your fridge and cabinets (and secret hiding places) and literally throw out the junk so that you can replace it with real food.

You can do it!

You can start fresh by giving new eating habits a try for three weeks. Substitute crunchy vegetables for your chips and fresh fruit for your cookies and candy bars. Add a salad to your lunch or dinner every day, and load it with dark leafy greens—spinach, kale, arugula are all good choices—you are adding fiber, vitamins, minerals, and phytochemicals your body is craving. If by the end of those 21 days you’re not feeling like a new person, then go back to your processed, hydrogenated, fiber-free standbys. Betcha anything you’ll be feeling so great that you won’t go back, ever.

The 21 days begins a lifetime of new eating habits that recognize the body’s need to keep your blood’s PH balance slightly alkaline. PH measures the degree to which a substance is acidic or alkaline. A diet that is slightly alkaline gives your body the important minerals (e.g., calcium, magnesium) it needs. A steady diet of acidic foods, on the other hand, can cause the body to “withdraw” necessary minerals from within itself to keep the bloodstream’s PH where it needs to be—leaving you vulnerable to illness and fatigue.

Go Green

Fresh juices and smoothies are a fabulous way to add dark leafy greens full of the minerals, vitamins, phytonutrients and chlorophyll your body craves into your diet. Start incorporating big salads with lots of veggies, wheatgrass, sprouts, fresh seasonal fruit, nuts and seeds to fill you up and keep your body in a mildly alkalized healthy state. You can also trade in your plate for a goblet or a go-cup. Leafy greens pair well with other veggies for delicious juices or smoothies. Experiment with different combinations, and you will quickly find one you’ll love. These wonder drinks are easy to digest and give you loads of vitamins, fiber—and good taste.

Hydrate, Hydrate, HYDRATE!

Here’s my lecture. Again. Get used to reading it, because this advice will find its way into everything I write: drink water! As we have discussed in the other posts, hydration is key to your body’s cleansing system. Begin the day on an empty stomach with a big heaping glass of hot water with lemon. The diluted lemon juice is alkaline and helps neutralize acids in your digestive system. A morning glass—make that a big glass—of water with a tablespoon or two of fresh-squeezed lemon juice also gives you your Vitamin C for the day, gets you system energized, and refreshes your body.

Keep it Moving!

The liver and kidneys are the body’s filtration system and work together to remove toxic waste from the body. The water you drink during the day helps these organs do their jobs and helps to flush out what your body needs to get rid of. It pays to keep these hard-working organs in tip-top shape by consuming foods that help cleanse of them. Beets, carrots, turmeric, grapefruit, spinach, avocado, apple, and dandelion greens or tea are great for this purpose. Add a few in to your daily routine!

Fill your plate as if you were casting a movie, using the simple guidelines below. Dr. Hyman recommends a diet that combines the principles of the Paleo diet (meat, fish, leafy veggies, fruits, nuts and seeds) and a vegan diet (any and all plant and plant-based foods), which he dubs the “Pegan Diet.” In a typical pegan meal, vegetables star, animal protein is a minor supporting player, and fruits, nuts, and seeds play the character roles to add flavor accents, texture and crunch. You might not win an Academy Award—but you will reap the rewards of health, vitality, and glow! Use this as a guideline: Fill your plate with ¾ greens every meal.

Give these small changes to your diet and habits a try for 21 days. The three weeks will fly by, but you won’t even notice, because you’ll be too busy loving the new, refreshed and healthy you!