"You can't outrun a bad diet" is just a bad take.

Even with running - especially with running - you can easily burn enormous amounts of calories.

There are two problems with this saying.

First, nobody knows what a bad diet is in the context of this saying. How many calories are we talking? How poorly balanced is the diet? Let's take a basic example: assume the perfect diet for a sedentary person, well balanced, exactly the right amount of calories, etc. Then on top of it, this person eats a 200g pack of Haribo 4 times a week. Surely this makes that diet insanely bad, right? Well, not really, it's only about 500 excess kcal/day which would be very easily compensated if this person had an active lifestyle. So how insanely bad does the diet need to be until the argument actually works? This saying is usually directed at people who want to lose weight, surely nobody is trying to lose weight in good faith if they drink soda daily, eat donuts left and right, and some haribos to top it off.

The second problem, is that people are scarily sedentary and view what should be a completely normal amount of physical activity as impossible. So what upper bound are we putting on the "running" part of the saying?

Doing 1-2 hours of sport 4 times during the work week, plus one longer physical activity on the week end (e.g., half a day hike or bike ride) is a completely normal amount of sport.

4-10 hours of exercise a week, for starters, is a lot more than what most people achieve. And it burns a ridiculously low amount of calories. Maybe ~300kcal/hour of excess calories burnt. That's ~3000kcal/week. You can ruin that in one sitting at Pizza Hut in under an hour.

If your goal is weight loss, and you have a choice between an extra hour of exercise, or eating one less Mars bar a week, skipping the Mars bar will be better for your weight loss.

Yes it's a lot more than what people "achieve", but it's the amount that people should be doing. Doing sport is not a chore that must be "achieved", it's a pleasant and relaxing activity that most people should be enjoying. The entire discourse around sport and physical activity is fucked up in the first place. When you hear public health official advising to do sport, they are almost apologising for it.

Counting kcal per hour of sport like that doesn't make any sense. 300kcal is 1h of brisk walking (non-sedentary people do it as part of their daily life, and probably don't count it toward their physical activity). It's also 1h of weight lifting, which most people would probably consider intensive sport. OTOH it's only 30min of jogging, which is a utterly trivial amount of sport for any healthy person. Those are rough approximations obviously.

After clicking the "reply" button of this post, I'm leaving for training with my sports club. 30min brisk walk each way to get there, and 1.5h of sport that is estimmated to burn 500kcal/h. Burning calories is trivial for active people.

That's the point though - if you get your fitness up then 600 kcal/hour should be possible on the bike and it should be sustainable to do day after day at that volume. Mix in the odd day of doing things super hard at 800-900kcal/hour and you're make an enormous difference to your weekly output.

If your goal is weight loss you should probably skip a mars bar every now and then, but I think you're underestimating what's possible after a bit of training and fitness improvement.

The exercise however will be better for your health and in the long term probably to weight loss too. The overall impact od sport on your body is not just calories burned.

I don't understand why people bring up totally ludicrous binge eating into this discussion.

Eating 3000 calories in one sitting is hard. Like, genuinely difficult, you're probably stuffing yourself uncomfortable and then in a food coma afterwards hard.

It reminds me of those silly TV shows with depressed 500lbs weirdos who just stuff their face all day. No-one normal is doing that. I mean christ it's only a bit less than half a kilo of straight mayonnaise.