The Promise

Imagine a diet that allows you to eat anything you want. You dont have to give up foods you love, count calories, follow special recipes, or plan meals.

That's part of The Shangri-La Diet, by Seth Roberts, PhD. He's a psychology professor at Beijing's Tsinghua University and a professor emeritus of psychology at the University of California at Berkeley.

On his plan, the only change you make to your diet is to drink 200-500 calories (1-4 tablespoons) of oil that doesn't have a strong flavor (like extra-light olive oil, flaxseed oil, canola oil, or walnut oil) every day.

Why drink flavorless oil? Roberts's theory is that people tend to like high-flavor foods that are strongly linked to calories, such as a chocolate-covered donut. Flavorless oil breaks that flavor-calorie link. So Roberts reasons that if you add some flavorless oil to your diet, you'll feel less hungry between meals and feel full faster at meals.

What You Can Eat and What You Can't

You can eat what you want.

Drinking the oil makes you less hungry, so you eat less and feel full faster, or so the theory goes. As a result, the plan maintains, you'll lose weight.

Roberts's plan includes these four rules:

Take 200 to 500 calories of oil daily.

Take the oil at least an hour away from eating food or tasting any flavors.

If the oil upsets your stomach, start small and work up.

If you havent lost weight after a month, increase your daily dose of oil by 1 tablespoon.

Level of Effort: Low

Adding the oil is the only change you need to make in your diet.

Cooking and shopping: Just your groceries.

Packaged foods or meals: No.

In-person meetings: None.

Exercise: Not required.

Does It Allow for Dietary Restrictions or Preferences?

Yes, because the only change is drinking the oil.

What Else You Should Know

Cost: The only extra cost is for oil, if it's not already on your grocery list.

Support: You can do this diet on your own. There are forums, and Roberts blogs on his Seth Roberts website.

Does It Work?

Roberts' website has a section devoted to the "science behind the diet," featuring testimonials from people who say the diet worked for them. Aside from that and Roberts' own report of losing 35 pounds when he tested the diet on himself, there are no studies backing up this plan.

Is It Good for Certain Conditions?

If you have high blood pressure, high cholesterol, heart disease, or diabetes, this isnt the diet for you. It doesn't address the nutritional issues you face when managing these conditions, like sodium for blood pressure or carbohydrates for diabetes. Also, the daily drink of oil adds calories most people don't need.

The Final Word

The strength of the plan is how easy it is to use. It may also help you better understand when youre hungry or full.

The downside is that it doesn't encourage healthy habits for the short- or long-term. This diet might appeal to you if you dont want to follow a strict plan or want any food or drink to be off limits. It's unlikely to work for you if you need a lot of structure or have health or emotional issues related to your weight.