Why Diets Don't Work: A Habit-Based Approach to Sustainable Weight Loss

When it comes to weight loss or maintaining a healthy weight, the first thing many people turn to is dieting. You know the drill—strict rules, cutting out entire food groups and fighting against food cravings. But here’s the truth: diets rarely work in the long term.

So, what does work? Habit change.

In this blog I explore what the evidence says about creating lasting change, and why shifting your focus from dieting to habit-building and taking a more holistic view of your lifestyle and environment can lead to more sustainable, empowering results.

What Are Habits?

Habits are the small, automatic behaviours we do regularly—often without even thinking (1). Brushing your teeth before bed, reaching for your morning coffee, or scrolling on your phone after dinner—these are all habits.

From a behavioural science perspective in simple terms: habits form when a specific cue (like waking up) triggers a behaviour (making coffee), which delivers a reward (a feeling of alertness). Over time, this loop becomes automatic – it becomes part of your routine.

Habits vs. Lifestyle Behaviours

While the terms habits and lifestyle behaviours are sometimes used interchangeably, they’re not quite the same.

• Habits are automatic and often unconscious. They're formed through repetition, in particular contexts, and are triggered by specific cues (1).

• Lifestyle behaviours are broader, more deliberate choices and patterns, such as going to the gym three times a week or cooking most meals at home (1). These may involve planning and conscious decision-making.

Think of habits as the building blocks that enable your lifestyle. When we work on creating healthier habits, we're laying the foundation for long-lasting change and taking deliberate actions to work towards our goals.

Why Dieting Doesn’t Work Long-Term

Dieting may lead to short-term weight loss in some individuals, but studies show that most who lose weight struggle to maintain it long term (2). When we lose weight quickly through severe calorie restriction, the body responds by lowering total energy expenditure, including energy burned at rest, during digestion, and through physical activity (2). Essentially, your body enters an energy conservation state where it reduces how much energy is burned during the simplest of daily tasks. This conservation state can last for years past the initial diet, making it increasingly hard to maintain weight loss. After all, food = energy, so if our body is compensating for less energy intake by expending less energy, then we’re back where we started.

Additionally, weight loss makes you hungry… when your energy intake decreases, your body responds by increasing the levels of the hunger hormone ghrelin, signalling to your brain to eat, and decreasing levels of the satiety hormone leptin, signalling your brain to keep eating—both of which make sticking to a calorie-restricted diet very challenging. These hormonal changes create a constantly stronger drive to eat, increasing appetite and cravings for quick energy foods - simple sugars and processed foods (which hit the bloodstream faster) - often leading to overeating and eventual weight regain (2), if not gaining more weight than when the diet started.

The Power of Habit-Based Change

So while research shows that diets generally don't work, habit-based interventions are proven to be more effective for weight loss than restrictive diets (2). Unlike dieting, habit change focuses on creating sustainable, positive behaviours that, with repetition, become automatic over time (2).

Instead of changing everything overnight, you focus on one small shift at a time. Here’s why it works:

• Realistic: Small habits are easier to stick to and integrate into your daily life

• Flexible: You can build habits that suit your lifestyle, preferences, and needs

• Sustainable: Habits are designed to last, not expire after 30 days

• Empowering: You’re in control, not following external rules

For example, instead of saying “I’m cutting out all snacks,” you might focus on a new habit like “I’ll include a protein-rich snack mid-afternoon to keep my energy stable.” It’s practical, supportive—and it works with your existing routines and your body, not against it.

Building Habits That Support Healthy Weight Maintenance

When you approach health and weight from a positive habit-based lens, you create a system that supports your goals without relying on willpower alone. Some examples of supportive habits might include:

• Eating regular meals to prevent overeating

• Pausing before eating to check in with your hunger levels

• Preparing a balanced lunch the night before work

• Keeping a water bottle nearby throughout the day

Over time, these habits become second nature—and that’s when the real magic happens.

If Habit Change Works So Well, Why Isn’t Everyone Doing It?

Here’s the thing: real, lasting change doesn’t come from quick fixes. It comes from shifting the way our brains respond to reward.

We live in a dopamine-driven world. Every scroll, every like, every instant purchase gives us a little “hit” of dopamine—a brain chemical linked to short-term reward. It feels good in the moment, which is exactly why so many diets rely on short bursts of motivation or fast results. But those quick hits fade just as fast, leaving us craving more.

To create meaningful, sustainable change, we need to shift from short-term rewards to long-term satisfaction. That means tapping into brain chemicals like oxytocin and GABA, which are linked to feelings of connection, calm, and deep accomplishment.

Ever felt that proud, grounded feeling after achieving something truly important - like it stayed with you for days or even weeks, your stress melted away and nothing could bring you down? That’s your long-term reward and regulation system at work. And it’s the key to building habits that actually last.

Our programs are designed to help you activate that system - not just for weight loss, but for lifelong change. Stay tuned - we’ll unpack the science behind it in an upcoming post.

Ready to Ditch Diets for Good?

At Thriving Habits, I help clients shift from restriction to sustainable routines that actually fit their life and enable their goals. If you’re tired of starting over every Monday and want to feel more confident and in control, I’d love to support you.

Book a one-on-one consultation today and start building habits that last.

References

1. Cleo G, Beller E, Glasziou P, Isenring E, Thomas R. Efficacy of habit-based weight loss interventions: a systematic review and meta-analysis. Journal of behavioral medicine. 2020;43(4):519-32.

2. Dulloo AG, Montani JP. Pathways from dieting to weight regain, to obesity and to the metabolic syndrome: an overview. Obesity reviews. 2015;16(S1):1-6.