Trendy then, tacky now. What more needs to be said about the fashionable attire for males in the 1980s?

The king of cool back then, Sonny Crocket, the main character on the trendiest of the TV shows, “Miami Vice,” wore v-neck t-shirts with double-breasted suits — but in crazy colors formally reserved for crayons. Flat-heeled loafers of the finest leather always adorned his feet and never — and I do mean never — any socks.

In short, so much that was coolish then strikes us foolish now, but we shouldn’t feel that way about the dietary trend of the times: stringently limiting the consumption of fat.

Yet about 15 years later during the no-carb craze, eschewing dietary fat seemed to make even less sense than wearing parachute pants, and conscientiously consuming “healthy” fat remains de rigueur to this day. A recent study, however, suggests eating a diet low in fat is indeed a good thing.

In women who have had breast cancer, doing so decreased the odds of early death, diabetes, and heart disease.

By analyzing the Dietary Modification Trial of more than 48,000 postmenopausal women that began in 1993 and ran nearly 20 years, Ross Prentice, Ph.D., and his colleagues at the Women’s Health Initiative found that those in the study who had already had breast cancer and followed the prescribed low-fat diet (which also increased their ingestion of vegetables, fruit, and grains) were up to 35 percent less likely to die from any cause when compared to the subjects who were instructed to eat as they had in the past by the conclusion of the study.

Moreover, the followers of the low-fat diet were up to 25 percent less likely to develop type 2 diabetes. Women who followed the low-fat diet and did not have a prior history of heart disease or high blood pressure were up to 30 percent less likely to develop any form of heart disease.

Even though this study only included older women, the research that led to the initial popularity of the low-fat diet also showed that it also did more than lead to weight loss. For example, Dr. Dean Ornish, probably the most vocal advocate of the low-fat diet, incorporated it into an overall plan that reversed heart disease in hundreds of patients.

Yet somehow in a matter of a decade or so, the low-fat diet went from being the way to lose weight and lessen the incidence of a number of serious diseases like heart disease, diabetes, and certain cancers to the reason why people were overweight or obese and at a higher risk of the those aforementioned afflictions.

What caused the change?

Ignorance. Ignorance that created a type of addiction.

In the 1980s when so many were turning to the low-fat diet as a way to lose weight, too many were ignorant of the fact that not all carbs are the same, that in the same way there are “good” and “bad” fats, there are “good” and “bad” carbohydrates.

What makes carbs “good” or “bad” depends upon how your body digests them.

Carbs that digest quickly in most instances are “bad” because they spike your blood sugar level and cause an excessive release of insulin, which more often than not leads to the double whammy of those calories getting added to the fat stores and creating new hunger. Carbs that do not digest quickly in most instances are “good” because they create a moderate increase in blood sugar and cause an appropriate release of insulin, which puts your feelings of hunger on about a three-hour hold.

For the most part, these “good” carbs are found in nature; the bad ones are found packaged in cellophane and pumped full of preservatives in grocery stores.

And they seem to have, to some extent, an addictive quality, the degree to which may be a matter of an individual’s physiology. These sugars added to so many prepackaged foods, however, have been found in multiple studies with laboratory rats to be as addictive as cocaine.

Related research with rats has found that “bad” fats consumed with “bad” carbs only increases the addictive quality. In fact, once rats get “hooked” on eating a combination of both, it alters the release of the neurotransmitter dopamine in their bodies.

Dopamine creates a feel-good feeling and is secreted as a result of normal eating. But when rats are accustomed to eating “bad” fats and “bad” carbs and then are fed healthy food, no such release occurs.

So much like a strung-out junkie, the search for a food fix begins.

So now can you see what ultimately happened to those back in the 1980s who believed they could eat any carbs at all with impunity?

And now do you recognize that you can consume the right sorts of carbohydrates, especially when consumed in conjunction with protein, and not have that inevitably lead to weight gain?

That a diet featuring “good” or complex carbs and high-quality but low-in-fat protein sources also decreases the incidence of disease only reinforces why you need to be aware of the difference between “good” and “bad” carbs.