The Low Down on Low Carb Diets

By Jonathan Berohn

With Thanksgiving just past and the Christmas season right around the corner, the annual diet season is also upon us.

This Christmas, my family and I are headed on a Disney cruise, so there’s been a little more sense of urgency associated with the whole diet business.  I must confess, I haven’t been as inspired as I’d like to be, but my wife has been much more earnest about the whole looking good in the bathing suit thing.  Which means we’ve either looked into or tried most of the major low carb diets out there and found some interesting results.

The Premise

Obviously, the main premise behind low carb diets is that we, as Americans, eat too many carbohydrates, and that’s why we’re collectively fat.  If we reduce or eliminate the low nutrition carbohydrates form our diet (refined sugars and non-whole grains being the main culprits) our metabolism will be much better able to process what we do eat, and we won’t be as hungry since the non-carb foods take longer to digest and are, accordingly more satisfying.

In addition to sounding basically sensible, there’s actually some reasonable science behind this whole low carb business.  When your body stores energy, the first thing it does is store it as carbohydrates.  When…if (ahem)…we lose weight, we have to burn off the extra carbohydrates our bodies store before we can even think about getting rid of any extra fat.  The real problem comes from the constant stream of carbohydrates we eat.  As they build up and our bodies max out on the carbs they can store, they turn those carbs into fat.  And we all know the rest from there.

Low carb diets try to break this cycle by eliminating this steady inflow of empty calories that we just end up packing away as fat.  The idea being that if stop consuming carbs, your body will burn up the carbs you have stored away.  Then, your metabolism will basically switch from burning carbs to burning fat.  The theory behind all these diets is that if you then don’t feed your body more carbs but keep eating things like proteins and fats, your body will become very efficient at burning protein and fat, and the excess weight will simply melt off as you are essentially removing the source of empty calories that drives the whole weight gain to begin with.

If you follow this kind of stuff at all, you have no doubt heard about some of the concerns nutritionists have about low carb diets.

Potential Problems

First of all, if you’re not careful, you can end up eating far too much fat, and you can ultimately end up trading being overweight for having high cholesterol and high blood pressure.  Pretty much all the diets have responded to this criticism in one way or another, though.  Even the Atkins diet, which was the original and most determined holdout, has acknowledged that unlimited high fat food really isn’t the best way to replace those carbs.  The latest versions of all the major low carb diets stress lower fat protein alternatives (translation—don’t eat bacon for breakfast, lunch, dinner, and snacks).

While dealing with the fat issue is not all that hard, the digestive side of things is a bit more challenging.  For the pure no carb diets (or the no carb cleansing periods some of the other diets prescribe) a major challenge is the lack of fiber in your diet.  I don’t think we need to digress into in-depth discussions about regularity, but I think you get where this is going.  When you aren’t even eating whole grains, you are very hard pressed to get enough fiber to avoid these problems.  It requires some serious foresight in meal planning and potentially some supplements like Fibercon or Metamucil.

The last problem is one that the diets don’t offer any quick fix for—maintaining your weight loss.  To be fair, pretty much every diet has the same problem to some extent.  It’s hard to keep weight off once you have finished your diet.  For low carb plans, however, this problem is a bit more acute, because it doesn’t seem likely that people are going to avoid carbs for their whole lives.  I know a number of people who have lost a fair amount of weight on one of these plans only to see it come right back on after they resumed more normal eating.  The plans do try to help ease the transition by slowly adding some carbs back in, but by and large it takes a lot of willpower to go from minimal carbs to well-chosen and moderated carbs.  Again, that’s not to say keeping the weight off is easy on any diet, but nutritionists will generally tell you that the best diet is one that re-trains your appetite, not one that simply denies it in the short term.  This is a problem that low carb plans have to deal with.