To carb or not to carb: that is the question. Whether ’tis healthier to avoid such fare and reduce the incidence of insulin resistance and diabetes or consume carbs in quantity to increase energy — and possibly weight gain and disease.

Aye, there’s the rub.

While you may argue it’s in poor taste to parody Shakespeare’s solemn soliloquy on contemplating suicide, research recent suggests it’s something else: appropriate. This research found that the percentage of carbs consumed by the subjects studied affected their life spans.

But let’s not get ahead of ourselves. After all, Hamlet only questions whether or not to end it all in Act 1 of Scene 3. Let’s review some of the carbohydrate research that preceded the publication of the life-span study.

In April 2015, a British Journal of Sports Medicine review asserted that an excess of sugar and carbohydrates in our diets, not a lack physical inactivity, is the reason why the rate of obesity has skyrocketed in the last two generations.

In fact, lead author, Dr. Aseem Malhorta, a UK cardiologist and consultant to the Academy of Medical Royal Colleges in London declared: “It is where the calories come from that is crucial. Sugar calories promote fat storage and hunger. [Poor diet] generates more disease than physical inactivity and smoking combined.”

Similarly, Valter Longo, the director of the University of South California’s Longevity Institute, offered this in response to recent research in a 2016 Time article: “Diet is by far the most powerful intervention to delay aging and age-related diseases. If you look at all the interventions that have ever been tried, diet has been proven superior to anything else.”

But a few perspicacious souls recognized the link between carb ingestion and quality of life more than a quarter of a century ago and started the study up for discussion today.

Researchers at Bringham and Women’s Hospital and the Harvard Medical School followed the diets of over 15,000 people for an average of 25 years and found that what is now considered a low-carb diet, one where fewer than 40 percent of daily calories comes from carbs, increased the risk of premature death.

What is now called a high-carb diet, however, one where more than 70 percent of daily cals comes from carbs, did so too.

Those middle-of-the-road folks who kept carb consumption to 50 to 55 percent of daily calories fared best. The researchers estimated that after those subjects turned 50, they lived to be an average of 83 years old.

That estimate is four years more than the low-carb-consumers estimate and one year more than the high-carb-consumers estimate.

As a double check, the same researchers reviewed a prior worldwide study of more than 400,000 men and women and again found that high- and low-carb intakes decreased life expectancy.

Now if you’re something less than a health-food fanatic and live for toasted white bread topped with jelly, a cruller with a cup of heavily sugared coffee, and French fries swimming in ketchup, you could argue that the loss of four years is well worth eating the foods you love. While that argument can be seen as a fairly rational one, here’s what I’d offer in response: Those who keep their carb ingestion between 50 and 55 percent — and eat “good” carbs rather than “bad” — add far more than time to the end of their lives.

They improve the quality of the second half of their lives. Considerably.

Better health, in essence, means a better ability to function. Those ingesting the proper ratio of carbs and living longer are also doing more during those later years of life.

They are not the poor souls afraid to drive or stuck in wheelchairs or in need of oxygen canisters.

Furthermore, if you know how to interpret the carb-ratio study, you can infer that consuming virtually all of your carbs as complex ones increases life span even more than the high-end estimate of four years. Though the study did not make a distinction between “good,” meaning complex and/or natural carbs, and “bad” meaning, processed carbs, work with the glycemic index, type two diabetics, and good old common sense suggest that being discriminate about your carbs — while eating the right amounts — would improve your health and your life span even more.

Your increased ingestion of fiber is one of the many reasons why. The more fiber you consume, the more short-chain fatty acids your digestive system produces, something that benefits your health in many ways.

Which is why how your body produces them and what you can do to increase the production of short-chain fatty acids is next week’s topic.