The other point on so many threads including this one is that 'you won't lose weight with exercise'. Baldly, that's true: you might burn between 250 and 450 calories in a CV exercise session but if you are eating unhealthily, you'll easily offset that. A few glasses of wine, a doughnut or two, or a big plate of pasta and you will consume those calories used by exercising.
But the broader story is that people who exercise will tend to eat better, not consume the food that leads to weight gain, will develop muscle (which burns more calories), will lose fat rather than tissue, if engaging in high intensity exercise will enhance their metabolic rate so that they continue to burn calories after exercise, and will have a better body shape so look leaner & toned.
Like everything it's very individual. I absolutely believe the people who say they don't lose weight with exercise & have to modify their diet. For some people, eating restrictively works for them (their personality, lifestyle, their body). But there's far too little recognition that what works for one person won't for another. Tuning into how your own body works, and what allows you to feel sated, strong & able to be active should be at the core of how people decide to eat.
I exercise daily, for a long time & know a core group of people who are all slim & toned. But they also look differently & from chatting to them I know they eat differently to me & each other too. Eg I need to eat something small before I work out or would collapse. Others couldn't face anything. Someone else needs to eat straight after our class whereas I can't eat for a good hour and so on.
The other broad truth is that people who eat very restrictively eg cutting out food groups; being very rigorous with intermittent fasting and so on, statistically find it hard to stick to. Of course individuals might but overall it's hard to maintain & when people stop restricting their diet, they often go back to eating unhealthily - so many posts on MN talking about losing significant amounts of weight then putting it back on at a later point.