04/16/2014 12:53 pm ET Updated Jun 16, 2014

Pulp Fiction? The Bottom Line on Juicing

Myth busting is an unpopular venture. The believer inhabits a more comfortable world than the skeptic. This is particularly true in the realm of health. Deflating the hope floated by promises of panaceas may inform but surely irritates. It combines the sting of loss with a sense of having been taken.

Too often the morning headlines tell us that the touted magical vitamin or medication or dietary regimen we just invested in either does nothing or will make us sick. But here goes.

Your juicer may belong on the shelf next to the other fallen health products. It is a device that takes healthy foods (fruits and vegetables) and renders them less healthy. It eliminates fiber, turns solid food into a liquid and facilitates a huge increase in consumption. None of that is good for you.

Fiber is the indigestible part of plant foods. Because it is not digestible, it slows digestion. And this has a powerful therapeutic effect. For instance, this makes you feel full longer. But there's more to it. Fiber also decreases the insulin response to the sugar in plant foods. This prevents hypoglycemia (the sugar level going too low), something that increases appetite.

Consuming something that is indigestible has surprisingly beneficial effects. Fiber significantly decreases the risk for developing heart disease, stroke, hypertension, diabetes, obesity, constipation and hemorrhoids. Fiber is one of the most important components of plant foods from a health perspective.

So why would you buy a machine that eliminates this stuff?

Let's look at the consequences of turning a solid food into a liquid. Research has shown that reducing the thickness of food increases the amount consumed by 30 percent or more. The most prevalent diseases of our time (obesity, diabetes, hypertension) are largely caused by the consequences of excessive food intake. Do we want to do anything that promotes consuming more calories?

It is unlikely that we will ever modify a natural food in a way that makes it better for us. Our genome is the product of 50 million years of evolutionary adaptation. Over this period, a system for extracting energy and nutrients from plants and animals was honed. Our digestive system is designed to break down, absorb and use these essential ingredients when presented in the form of natural food. Attempts to identify the parts of food we need (vitamins, minerals, proteins, antioxidants...) and consume those things in place of an adequate diet of food have disappointed.

How might we improve our assessment of things that supposedly are good for us?

Here are some tips.

Beware of any health trend that turns a noun into a verb (e.g., juice to juicing).

Avoid anything that promises to do all of the following: slow aging, improve mood, prevent cancer, eliminate fat, increase muscle mass, erase wrinkles, strengthen cognition and increase libido (unless it's exercise).

Never buy a product that is intended to replace real food. There is no substitute for real food.

Douse in doubt anything that suggests it can deliver on something that requires time, discipline, change in behavior, and hard work, without time, discipline, change in behavior and hard work.

Focus on living meaningfully not living longer.