Christine Dougherty claims she lost 54 pounds in two years, which comes to about half a pound per week. Why is this news? Because Christine wasn’t really on a diet. She ate like millions of other Americans eat every day – mostly fast food and such. And like millions of other Americans, she ordered, purchased and consumed her meals in her car. Her preferred eatery was (and still is) Taco Bell®, also because it is conveniently located next to her home. Since neither she nor her husband are inclined to cook, it is only natural that they have developed eating habits that are easy to satisfy and fit their busy lifestyle.

When Christine eventually reached her weight loss goal without ever giving up on her fast food fetish (so we are given to believe), the husband encouraged her to write a thank-you-note of sorts to Taco Bell® headquarters and tell them the great news – namely that she got thin from eating their tacos. The rest is history, or perhaps the stuff fairy tales are made off. Christine is now an official (and supposedly well-paid) spokesperson for Taco Bell’s® latest ad campaign called “Drive-Thru Diet.”

Of course, Christine did not lose weight because she ate lots of tacos and burritos, but rather because she managed to reduce her calorie intake. She could have accomplished that with any kind of food. It is actually surprising that it took her so long to shed 54 pounds, considering that a 500 calorie reduction per day allows most people to lose one pound per week.

Taco Bell’s® ad campaign is by no means original. A few years ago, another happy customer, Jared Fogle, became the poster boy for Subway®, when he professed that his weight loss efforts succeeded simply by sticking to a Subway® “sandwich diet.”

In all fairness, it must be said that Taco Bell® has never suggested that its products are designed for weight loss. However, when you see Christine on the home page of the company’s website holding up her old pants, made for someone twice her size, one must admit that the hints are less than subtle.

All that aside, it is gratifying to see that more consumers are looking for health-conscious alternatives to their traditional food choices, and that even fast food chains are taking note. For instance, McDonald’s® “Go Active” meals and Pizza Hut’s® “Fit N Delicious” were created in response to this trend. In principle, this is a welcome change and should not be dismissed as pure sales gimmicks.

Taco Bell’s® “Drive-Thru-Diet” caters to customers who are too pressed for time to linger in a restaurant or supermarket, but still want to make better diet choices. Seven items on the menu have detailed information listed about calorie and fat content. At a first glance, the numbers look reasonable: Between 150 and 340 calories and 8 grams or less of fat per serving is not bad.

The picture changes, however, when you realize the high levels of sodium. Three out of seven items contain more than fifty percent of the recommended daily allowance of 2,300 mg of sodium. For people who suffer from hypertension and heart disease, the tolerable dose would be lower, about 1,500 mg. In other words, one “Drive-Thru-Diet” meal almost covers your allowance for the whole day. Again, for folks with hypertension or heart disease, eating this kind of food on a regular basis will only make matters worse.

What does all that mean in practical terms? Well, for one thing, it means that there is no substitute for cooking healthy meals from scratch and with fresh ingredients. I congratulate Christine and everyone else who has managed to lose weight in any which way. But I would also advise you to take some cooking classes and start cutting back on foods you can eat in a hurry.

Timi Gustafson R.D. is a clinical dietitian and author of the book “The Healthy Diner – How to Eat Right and Still Have Fun®,” available in bookstores, at her blog  http://www.timigustafson.com and at Amazon.com. You can also follow Timi on Twitter at http://www.twitter.com/TimiGustafsonRD