Think weight-loss and what's the first diet tip that comes to mind? Trending among Celebrities is the gluten-free diet which cuts carbs and sugar. The TLC reality TV show "My 600-lb Life" pushes such a sugar-free, carb-free diet after bariatric surgery. But carb lovers, don't pass up the pasta just yet. Health experts are saying that no carb, no sugar diets are no good for shedding obesity. Here's the tasty truth behind their surprising advice.

Health gurus take a bite out of celebrity diets

So if you eat pizza, chips, fried chicken and chocolate cheesecake every day you stand a good chance of ending up on "My 600-lb Life." Those foods are among the leading causes of obesity and gastric bypass surgery.

But you can eat some carbohydrates and still slim down. The key lies in portion control and sustainable diet changes, says dietitian Andy Bellati and exercise pioneer Philip Stanforth.

But moderation is where most celebrity diets fail. They immoderately cut out entirely essential food groups like bread, grain, and starch. Even reality television's Dr. Nowzaradan's bariatric surgery diet may be too restrictive.

Cut carbs, gain weight?

What's the beef with Dr. Now's famous "My 600-lb Life" diet? His ketogenic-like, high protein meal plan has helped Bettiejo Elmore, Chad Dean, Christina Phillips, rebellious Steven Assanti and countless others achieve weight-loss. The problem isn't with what reality TV patients eat but what they don't.

To shed obesity, folks avoid "white food," eliminating rice, potatoes, bread, pasta, and sugar (a.k.a. gluten). But the experts agree that unless you are really gluten intolerant (most people aren't) or have Celiac disease (few people do), a gluten-free diet will do more harm than good.

Benefits of low-carb vs. no-carb diet

Healthy carbohydrates are natural appetite suppressants.

Good carbs, which are low sugar, high fiber, and balanced with protein, are satisfying, filling, and curb hunger. Eating vegetables and fruit only can actually make you hungrier. No-carb diet foods may be higher in salt and that sodium stimulates appetite, edema (water retention) and weight gain.

Carbohydrates, cravings, and curbing hunger

The problem with eliminating carbs are numerous. It can cause a food allergy where none existed. Folks who weren't gluten intolerant develop an intolerance by avoiding it. Skipping carbs, which are arguably the more fun foods, puts the body into deprivation mode. This spurs cravings, which most "My 600-lb Life" stars agree makes it so much more difficult to lose weight. Cutting foods may work in the short-term but over time it's virtually impossible to maintain.