In 1980, the U.S. Department of Agriculture issued America's first national dietary guidelines. They recommended that people dramatically reduce your intake of fats — all fats.

But eventually, folks realized that a low-fat diet fueled the intake of processed carbs and added sugars.

So, along came low-carb diets, loaded with saturated fats from meats and dairy, and short on high-fiber foods. Not smart either.

What's a hungry person to do?

Well, a study published in JAMA Internal Medicine looked at the health effects of food quality in 40,000 adults and gives a clear answer. 

Poor quality, poor results: 

• Eating a low-carb diet that's missing high-quality, unprocessed carbohydrates and is loaded with animal protein and saturated fats raised the risk of death from any cause by 7% over the 15 years of the study.

• Eating a low-fat diet that slashed good-for-you fats like olive oil, so you're not getting the healthy odd omegas (odd numbers, not peculiar!) such as omega-9 and omega-3, along with sat-fat dairy, and relied on low-quality, processed carbs led to a 6% increased risk for early death during the study.

High quality, good results:

• A healthful low-carb diet that dodges low-quality processed carbs and added sugars and contains unsaturated fats and high-quality protein from minimally or unprocessed plants triggered a 9% lower mortality risk over 15 years.

• The best plan, however, was a low saturated fat diet loaded with high-quality carbs and plant-based proteins with plenty of odd omegas. It was associated with an 11% decreased risk for all-cause mortality over the same 15 years.