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Why Most Diets Fail – And What to Do Instead
August 11, 2025
We’ve all been there. A new diet starts strong – lots of water, salads, maybe even a shiny new blender.
But a few weeks in? You’re hungry, frustrated and trying to figure out how that one cookie turned into four.
The good news is, your willpower might not be the problem.
“Diets rooted in strict rules or heavy restriction tend to backfire,” says Ulysses Wu, MD, with Hartford HealthCare. “You might see results at first, but it usually isn’t sustainable. Eventually, your body – and your mind – will push back.”
So why exactly do diets fail, and how can you break the trend? We asked Dr. Wu to dig into the psychology behind it.
Diets get harder as time goes on.
No, you aren’t imagining it – diets fail in part because they become more difficult to follow over time.
“In the early stages of a diet, it likely feels easier to cut calories, skip snacks or eliminate entire food groups,” says Dr. Wu.
And while that might lead to quick weight loss, it also causes your metabolism to slow down, and your hunger hormones to ramp up.
“That’s your body’s way of protecting itself,” says Dr. Wu. “It doesn’t know you’re dieting – it thinks you’re starving.
Before you know it, your cravings will become more intense, and old habits creep back in – one more reason why diets fail over time.
> Related: Fad Diets: The Way to Lose Weight, or a Bunch of Baloney?
The hardest part of dieting is often mental.
As soon as something is labeled “off-limits,” your brain naturally starts to want it more – and food is no exception.
“Have you ever sworn off carbs, and found yourself dreaming of pasta the next night? That’s called deprivation thinking, and it’s recipe for binge eating,” Dr. Wu cautions.
That all-or-nothing mindset is often what kills diets.
“If you’re trying to follow a strict diet with no cheat meals, and give up all of your favorite foods, you’re setting yourself up for disaster. As soon as you mess up once, you might be tempted to give up entirely,” says Dr. Wu. “That’s why giving yourself room for flexibility is so important.”
And what’s more – the food industry is working against you.
“It’s their job to sell you food – whether it’s healthy or not,” says Dr. Wu. “This can be difficult to combat, as their marketing is designed to undermine your resolve and will-power.”
> Related: What to Eat When You’re Stressed
One off day doesn’t mean you’ve failed.
Did you have a tough day, and stress-eat your way through the pantry? Not to worry.
“Health is never about perfection,” says Dr. Wu. “It’s about consistency over time. The real danger isn’t one bad day, it’s the spiral that can follow – skipping meals the next day to make up for it, doubling down on unrealistic restrictions, and feeling generally defeated.”
Instead, focus on your next meal, drink some water, and remind yourself why you started.
> Related: The Problem With the 2,000-Calorie Diet
Try these 7 tips instead.
Another diet probably isn’t the answer. Instead, try shifting your mindset, building new habits and allowing them to grow.
Here’s how to get started:
- Drop the guilt. Food isn’t inherently “good” or “bad.” When you stop assigning morality to your meals, it’s easier to make thoughtful, balanced choices.
- Don’t wait until you’re starving. Skipping meals sets you up for overeating later. Instead, eat consistently throughout the day and prioritize protein, fiber, and healthy fats — the trio that keeps you full longer.
- Practice mindful eating. Eat slowly, put your fork down between bites, and check in with your hunger level halfway through. At restaurants, ask for a to-go box upfront or share an entrée.
- Plan ahead. Keep healthy snacks on hand, prep meals when you can, and never go grocery shopping hungry. Small steps like these can help prevent impulsive decisions.
- Enjoy your favorite foods. Yes, really. Depriving yourself usually leads to giving in. Instead, allow yourself a treat now and then, and truly enjoy it. No guilt required.
- Learn to eat for hunger rather than cravings. We have all been there – you didn’t think you were hungry, until a delicious food showed up on your Instagram feed. Train yourself to recognize the difference between cravings and hunger.
- Understand that your health is a marathon, not a sprint. Just like a foot race, you might achieve huge gains during a sprint – but you can’t do it forever. Healthy choices are long-term, so it’s okay to have bad days.
“This is a big one,” says Dr. Wu. “You have to find a balance that works for you. For example, I try to eat sensibly from Sunday evening through Friday afternoon, and allow myself to indulge a little more from Friday night through Sunday during the day. The gains that I make eating healthy during the week will overtake my indulgence on the weekend – plus it gives me something to look forward to.”
Sustainability is key.
“Dieting is a short-term solution, at best,” says Dr. Wu. “You can use it as a reset, or an opportunity to retrain your brain for some quick gains over a few weeks or even a couple of months.”
But beyond that, it’s less about dieting and more about healthy habits. Diets fail because they’re built to be short-term. Real, lasting change comes from building habits that support your life — not take it over.
“You don’t need a new diet,” says Dr. Wu. “You need a new approach to a sustainable life.”