I’ve spent much of my adult life avoiding exercise, pretending that wine doesn’t have calories, and losing—and regaining—the same 25 pounds.

And yet, once again, this January I’m joining the masses of people resolving to get fit and trying to shed the extra weight, once and for all.

But this time, at least, I’m going in armed with knowledge, culled from an enormous body of research about diets. Turns out, there are many reasons diets fail more often than they work—and a few ways you just might be able to make them work better.

Here are 10 key truths about dieting that may make it easier to actually stick to your resolution this time. And, if nothing else, they’ll at least help you keep your efforts in perspective.

Dieting is a $70 billion industry 

Let your taste buds savor this for a minute: The diet industry is basically successful because we—dieters—are not.

Or more accurately, we’re successful for just long enough to make it seem like it’s possible. Yet through the years, the Centers for Disease Control has reported that 95% to 98% of all dieters fail to keep off the weight they’ve lost for three years.

Dieting research is skewed

The CDC uses three years as the benchmark to determine whether a diet has been successful—and defines success as keeping off the weight you’ve lost. Yet most obesity research only follows people for 18 months or less.

Critics say this renders most weight-loss studies inaccurate at best and, among skeptics like me, downright deceptive at worst.

Oh, and yes, much of the diet research is sponsored by the diet industry.

There is another big problem with a lot of that research: Dieters lie. Or put more kindly, we underreport what we shovel into our mouths.

In part, we don’t measure accurately or understand portion control. More on that below.

But with all the technology out there that enables researchers to track whatever they want to measure, you’d think that if someone really wanted to collect our data they would go further than to just ask us.

It’s not your fault

If anyone should be able to accurately report her dietary intake, it would be me. (Aside from the wine.)

But the various methods I’ve heard to describe portion sizes are baffling, if not downright disgusting.

The correct portion size for chicken breast, for example, has been compared to a deck of cards, my fist sliced lengthwise (a lovely image, no?), and/or the size of half of a long envelope.

That last one sent me scrambling for a long envelope and wondering who actually sends snail mail any more. But at least I got some steps in!

It may be Dr. Delboeuf’s fault

Delboeuf’s illusion is an optical illusion about size perception. It’s led to a popular weight loss tip that says if you eat the same amount of food off a smaller plate you can trick your brain into feeling full. The same amount of food on a larger plate leaves us feeling that we have eaten less—and still hungry.

Is that actually true? There’s a hung jury.

In a 2012 study, researchers had people serve themselves soup in different sized bowls. The bigger the bowl, the more soup people took, leading the study team to conclude that the Delboeuf illusion was indeed at work.

But not everyone agrees. Israeli researchers tested the Delboeuf illusion on people  who had eaten just before the experiment vs. those who hadn’t eaten for three hours and were presumably hungry, according to a paper published in Scientific American. The hungrier ones still guessed more accurately about how much pizza was on the plate, suggesting that some of our brains are beyond tricking.

Confused? Try this takeaway: Studying dieters’ habits is also a big business.

One research team compared plates with thinner rims to plates with heavier rims to see which one left dieters more satiated. However, I’ve never been hungry enough to eat the plate so the point of this study eludes me.

A valid email is required

It’s probably your mother’s fault, too

Aside from this statement’s massive applicability in so many situations, Mom was likely the one who taught you to clean your plate. Cleaning your plate is bad advice in today’s Dietworld. Leave something on it for the dog to lick.

Not cleaning your plate is especially important when you eat out in restaurants, where serving sizes are typically twice the normal portion.

Some diets just don’t work

You know this already, but it doesn’t stop the diet industry from trying. And knowing this hasn’t stopped me, either. 

As a rule, I am drawn to the diets that preach a lifestyle change—Weight Watchers, MyFitnessPal, Noom, even the old Pritikin diet for those who go way back with me. I’m not a fad dieter and have never ascribed to diets that want me to eat grapefruit with every meal (Grapefruit Diet) or eat only what prehistoric man ate (Paleo) or the Wine and Egg Diet where you mostly eat eggs and drink half a bottle of wine a night for dinner.

Still, if you’re mulling over the latest weight-loss plan that your friend is touting on her Facebook page, it doesn’t hurt to take a look at this research out of UCLA, which analyzed 31 major diet studies and found an altogether “bleak picture of the effectiveness.”

The first week’s the charm

The beginning is always the hardest part. Two out of every five people on a diet quit in the first week. After a month, only one in five are still at it. So hang in there.

Hangry is real thing

Hangry is a great portmaneau of hungry and angry, which describes the state of irritability that hunger leaves us in. It’s also a great reason to not follow a diet that leaves you hungry. Think of your loved ones.

Diets may actually be bad for you

The UCLA study also concluded that diets aren’t just unhelpful—they’re downright bad for you.

Given my propensity toward being hangry, my family members might agree.

But the real issue is our tendency to regain the weight we lost—and then some. The study concluded that most people would have been better off not going on the diet at all because ultimately their weight would be about the same, and their bodies would not suffer the wear and tear from losing weight and gaining it all back.

Yo-yo-ing is definitely bad for you

Yo-Yo dieting describes the pattern of losing weight, gaining it back and then dieting again. It’s real name is weight cycling and it’s common—10% of men and 30% of women have done it. Me included.

And it’s actually bad for you. Yo-yo dieters experience an increase in body fat percentage,  have an increased risk of developing Type 2 diabetes, and are at higher risk for heart disease.

That’s not meant to offer an excuse to give up trying to lose weight. It simply underscores the importance of keeping it off, once you do.

Arming yourself with knowledge helps. At least that’s what I’m telling myself this January.