J.R.R. Tolkien, author of “The Hobbit,” once said, “shortcuts make long delays.” He may have been referring to navigating through tough terrain, but he would have been spot-on if he were talking about weight loss. Recently the Food and Drug Administration warned about online products that promise shortcuts.

• FDA alarm No. 1: Unauthorized versions of fat-dissolving injections for use on the chin, back, thighs, underarms and stomach, turn out to deliver a combo of ingredients (phosphatidylcholine ... and sodium deoxycholate) linked to serious side effects, including “persistent scarring, severe infections and skin deformities.” There’s only one injected fat dissolver (only for under the chin) that’s FDA-approved and it’s administered by a health care professional.

Dr. Mike Roizen is the founder of www.longevityplaybook.com, and Dr. Mehmet Oz is global adviser to www.iHerb.com, the world’s leading online health store. Roizen and Oz are chief wellness officer emeritus at Cleveland Clinic and professor emeritus at Columbia University, respectively. Together they have written 11 New York Times bestsellers (four No. 1’s).