The idea behind most diets is totally stupid

When it comes to diet, easy advice always seems to win out over good advice.

"Watch your portions and don't eat too much processed food" may be tried-and-true, but it won't lead to instant or drastic results, and it won't make anyone rich. It's much easier to, say, just cut out this ONE EVIL THING - saturated fat, sugar, gluten ... whatever the maligned food of the moment is.

The truth is that there's a disconnect; foods are not bogeymen. Eating too much is bad, and eating too much from a particular food group is often bad.

"What's getting harder to justify, though," writes Aaron E. Carroll, a physician and columnist for The Upshot at The New York Times, "is a focus on any one nutrient as a culprit for everyone."

Anyone can cherry-pick nutrition studies to suit a particular agenda. Yet while "we seek a singular nutritional guilty party," Carroll writes, the real problem is quite simple: "We eat more calories than we need."

That's why it shouldn't be surprising that reducing calories, however you choose to do that, is a pretty effective weight loss strategy. Last year, a major analysis of a wide variety of diets found that they all worked, at least to some extent. The diets were all different - some low-carb, some low-fat, etc. - but they had one thing in common: lower calories.

In other words, most diets tell you to eat less of one thing - but it's a ruse. The real goal here is just eating less, period. Cutting one thing out may help you do that in the short-term, but that doesn't mean that thing is inherently bad.

Still, some eating plans are easier than others. Extreme regimens that cut out a whole food group are often hard to stick to. And that's what you really need to figure out if you're trying to eat better: not which nutrient is the enemy (spoiler alert: none are), but how you can eat healthily over the long-term, not for just a month or a year.

"What isn't helpful is picking a nutritional culprit of bad health and proclaiming that everyone else is eating wrong," Carroll writes. "The best diet is the one that you're likely to keep."