Most diets collapse not because people don’t know what to eat, but because willpower is a limited resource. You might resist the cookie at 10 AM, but by 10 PM, after a stressful day, your brain is exhausted. Decision fatigue kicks in, and you give in.

Psychologists like Roy Baumeister have shown that self-control functions like a muscle — it gets tired with overuse. That’s why diets that require constant monitoring (“track every bite, log every calorie, resist every temptation”) almost always fail long term.

So what works instead? Habits and structure. When a behavior is automated, it no longer drains willpower. Brushing your teeth doesn’t require motivation — it’s just something you do.

Intermittent fasting, especially with apps like Fastry, leverages this principle. By setting clear eating windows, you remove dozens of tiny decisions: Should I snack now? Is this allowed? How many calories? The structure acts as an external willpower, making it easier to stick with healthy choices.

It’s not about being stronger — it’s about making the path of least resistance the healthiest path.