I actually lost three stone during lockdown (between about this time last year and May 2021) and put it all back on again when I returned to the office (think nice cafe, crisps, chocolate, vending machines etc.)

Basically, when I was at home I planned everything I ate. Porridge for breakfast, homemade soup (a batch lasts four days) and bread for lunch and a proper dinner, such as a big batch of curry, chilli, stew (each lasts a few days ) plus veg.

I also exercised. I dusted down the old exercise bike and did 20 minutes most days followed by some basic calisthenics plank, pushups, airbike and crunches. I started with low numbers, so 60-seconds plank, 10 pushups, 15 airbikes, 20 crunches and then every added a few seconds/reps each day. Excel is your friend.

You'll be amazed at how much improvement you can achieve when it is structured over the space of a couple of weeks.