As I dietitian, I’m frequently asked whether cleanses are safe. There seems to be a deep fascination with cleanses out there—they carry a promise of pushing a reset button and purging your body of all those "toxins" that supposedly are building up. Cleanses usually take one of two turns: juice cleanses (replacing all solid foods with freshly pressed organic juices) or water cleanses (essentially fasting and just drinking water, and maybe adding a dash of lemon juice, cayenne and maple syrup a la the Master Cleanse).

Your body already has organs dedicated to eliminating toxins from your body—your liver, kidney and intestines. And these organs work best when they’re being used (i.e., when there is food to digest). The best thing you can do is to limit your exposure to chemicals and toxins from the get-go and support your body’s natural detoxification system through healthy whole foods (think plenty of water, organic fruits and vegetables, whole grains and lean protein).

For most people, a day- or two-long cleanse is safe, although you may feel lightheaded, tired and hungry from not taking in extra energy through food. Following a cleanse for a longer period of time could find you missing out on critical nutrients. And cleansing can be dangerous if you have certain health conditions (diabetes or other chronic disease, pregnancy or nursing, for instance).

No doubt, if I’ve had a day or two (or three) of rich food—hello, holidays—then I naturally crave plainer, lighter, healthier food. Salads and veggie soups, or a pile of steamed kale sound particularly good to me. The key is to pay attention to your body and the signals it’s sending you. If you’re feeling tired, sluggish, and overloaded, then yeah, by all means cut back on the rich and processed stuff and be gentle to your body, but don’t feel compelled to “cleanse.”

Kerri-Ann Jennings, MS, RD, is a registered dietitian who thinks you don’t have to compromise good taste to achieve good health. A former associate nutrition editor of EatingWell Magazine, Kerri-Ann now freelance writes about food, nutrition and health trends and her work has been published on FoodNetwork.com, Yahoo! Shine and the Huffington Post, among others. She also puts her masters degree in nutrition from Columbia University to use teaching classes and counseling individuals on adding healthy behaviors to their daily lives. Find more of her work at kerriannjennings.com or follow her on Twitter @kerriannrd or Facebook.