We all know the story. And the stats. Some 90% or more of weight loss diets fail, and many dieters actually end up heavier. What’s going on?

Are these dieters just lazy? People who’ve never had a weight problem would say so. “Eat less. Move more.” It’s so simple, right?

Short answer: no.

There are a number of factors that help us unpack aphorisms like “eat less, move more” and “calorie in, calorie out.” In short, it’s all relative to your unique factors: food processing genetics, microbiome, age, hormones, gender, viruses, and more.

At some level, yes, within each individual’s body situation, “eat less, move more” may be true.  But how much less and how much more?

The details are too many to discuss here (it would take a book!). So take our word on it for now.

How does this relate to yo-yo dieting?

One key finding is that when you lose fat—like that first 10 pounds that you quickly dropped on your latest diet attempt—your body signaling changes. This is because key signaling hormones are produced by fat itself. The fat goes down, the signaling slows, and profound changes occur.

These changes make you feel hungrier and burn less calories than people never heavier than your new weight. Feeling hungrier, in this case, doesn’t just mean a little bit of tummy growling.

Your brain is going to react differently to food. Seeing food, smelling food, even thinking of food, will all cause stronger emotional reactions than they would have at your starting weight. You will crave more calorie-dense foods. Furthermore, depending on the foods you now eat, you may alter your microbiome. And you’ll feel too strained to exercise as much as you’d like to (because you’re feeling the need to overcome that slower metabolism).

As all these forces align, you fall off the program. The weight goes back up, like that yo-yo.

So you try again on another plan. Same thing. Only the effect is greater. Each time you lose and gain you risk further disturbing your bodies signaling around hunger, digestion, fat storage, insulin sensitivity and a host of factors. On top of it all, your will power, confidence, and mood are taking a beating too.

Would you be better off never trying?

Not knowing what you were getting in to, frankly, yes. The mission was doomed to fail. And the more you yo-yo, the worse your health is getting. It’s literally killing you.

Losing weight and getting rid of fat really strikes a nerve in us modern humans. And we seek silver bullets. Unfortunately, many dieters put more research into choosing a flat-screen TV or a new laptop than they put into choosing a diet plan. (TV manufacturer’s—maybe you should claim to change people’s lives in 10 days.)

To break the yo-yo cycle, you have to put the work in up front and along the way.

First, barring outright snake oil, some people will respond to a particular diet and exercise plan. Keep in mind, though, that your friend who got great results was lucky to have hit on a diet that was aligned to their factors. That doesn’t make the same plan right for your context.

So think about what worked for you and what didn’t in the past. Look for patterns.  Can you eat a moderate amount of carbohydrates—grains and veggies—as long as you don’t overdo the sugar cookies? Or does being in the same room as a banana make you gain weight?

Next, exercise. You’ve heard that building muscle mass will raise metabolism and help you burn fat. True. And you’ve read that high-intensity interval training (HIIT) is a super fat-burner. True again. But, you recall, that when you have done intense exercise, weights or HIIT, it made you so hungry that you overcompensated on the calories. It could be that low-intensity steady state (LISS) workouts will be better for you in the long run.

The point is, you have to research, learn, and experiment to understand what factors are most important for you.

Only then can you get off the yo-yo train.