10 reasons you're not losing weight even though you're on a diet

If you've already lost some weight on the diet, you may have reached a so-called "plateau" due to metabolic adaption.

That means your smaller body may require a different number of calories than when you first started out on your new plan, Insider's Rachel Hosie previously reported.

"If you're medically overweight, you can lose 20 to 30 pounds in a few months by eating the right amount of calories, registered dietitian Fatimah Fakhoury told Insider. "That's not going to last forever."

But while often people need to eat fewer calories to continue to experience weight loss, that's not always the case, she said.

For example, some people find exercise is easier after they lose some weight so their calorie needs can stay the same and they'll still lose weight.

Eating too little — say, 1,000 calories a day — can prevent you from losing weight, too.

"When you don't eat enough, your body is starving and it's not going to lose any extra weight" because it needs those energy stores to keep you alive, Fakhoury said.

Seriously restricting your intake can also make you too tired to keep up physical activity, not to mention makes you unhappy, Fakhoury added.

Eating all of your calories at one big meal rather than throughout the day "really slows your metabolism down," hindering weight loss, Fakhoury said.

If that meal is late, it can be especially problematic because you're likely famished and eager to reach for processed choices rather than something more balanced.

Research shows that eating your largest meal in the morning, however, is associated with more weight loss — even if you don't eat any fewer calories across the day.

Sleep is an overlooked factor that's essential for weight loss and maintenance.

One study found that, compared to sleeping eight hours at night, sleeping just four leads to eating 559 more calories the next day. Another showed that reducing sleep by three hours a night for 10 nights led to less fat loss and more lean body loss among dieters.

That's in part because of the way sleep deprivation activates hunger hormones, and also because being awake longer leaves more opportunities to eat, personal trainer Ben Carpenter previously told Insider's Rachel Hosie.

Fakhoury often sees clients who are eating well, exercising, sleeping, but still heavier than what feels healthy for their bodies.

In some cases, she says, "it turns out they have an underlying cause," like pre-diabetes, which affects more than 1 in 3 Americans, according to the CDC.

Others may have a thyroid problem or hormonal changes, like from perimenopause, that affect their ability to lose weight.

It's not just how much you eat, of course, it's what you eat.

A balanced diet with plenty of whole foods is going to support weight loss and maintenance in large part because it will keep you satisfied.

Protein is a particularly important component of a sustainable weight-loss diet, since eating 25 to 30% of your calories from it can boost your metabolism by 80 to 100 calories per day, according to Healthline.

Protein also affects your appetite-regulating hormones, which can lead to fewer cravings and less snacking — weight-loss disruptors on their own.

If you're restricting your food (and drink) intake four days a week and then throwing caution to the wind the other three, the math balances out: you're not going to lose weight, and may even gain it.

That's why finding a pattern of eating that's sustainable for you — which allows for flexibility but doesn't spur binge-eating — is critical for a healthy body and mind, whether or not it includes weight loss.

Dieting to to fit a societal belief of what "healthy" looks like (thin) can be exhausting, leading people to quit diets and regain the weight that was perfectly healthy on their bodies to begin with.

Remember, research shows weight and body mass index are poor indicators of health.

Your behaviors — like moving regularly in a way you enjoy, managing stress, and eating in a way that supports your body, mind, and relationships — matter more.

"The ultimate goal is to have food become one of many aspects of life that support your well-being, but it doesn't take on this outsized role where you're spending all your time worrying about food and nutrition,"registered dietitian Christy Harrison, host of the Food Psych podcast, previously told Insider.

Intuitive eating, she said, gives you time to think about other things that matter in your life."

• Read more:
• 'Intuitive eating' is on the rise, and experts say it's because people are fed up with diet culture
• People are protesting the Weight Watchers 'healthy eating' app for kids, citing toxic diet culture and experiences with disordered eating
• Belly fat may be linked to a higher risk of early death, regardless of overall body fat
• Going on a low-carb diet could be more effective for weight loss than cutting calories, especially for people with insulin resistance