Exercise is obviously good for you, and I'm assuming you're being told to lose weight to lower the risk of a heart disease. So walking is a great start. It's also great for your mental health, especially if you've got some good podcasts to listen to.

Don't dismiss weights, either. You don't have to turn into Arnie and go full on gym bro, but lifting weights is proven to be more beneficial for weight loss than cardio. Just take it easy and know your limits.

That said, it doesn't matter how much exercise you do, as the majority of weight loss is achieved in the kitchen, not the gym. If your GP can refer you to a dietician who can create a diet plan for you, great. If not, avoid added sugars like the plague, cut down on portion sizes, and avoid things that are high in fat. And drink a lot more water.

The key here isn't to achieve the goal of losing 2 stone, it's to make subtle changes in your lifestyle that become habits. Otherwise you'll lose the 2 stone and then just revert back to type.