Portion control is only cooking/serving theexact amount of food you know you will eat. I serve all meals for the two of us directly onto our plates, so no waste of vegetables, rice potatos etc. I cook meat dishes using 1lb of meat in one go and serve onto plates and into freezer containers to go onto the freezer. Obviously there will be occasions when one of us isn't hungry and leaves food, but that is very rare. Most people eat roughly the same size meals almost all the time. We rarely snack or nibble between meals so that doesn't blunt our appetite for meals.
The purpose of consume by dates is to do with how long the food will remain in perfect condition. It is a short as possible because manufacturers do not want consumers complaining that they left a piece of cheese on a plate in the kitchen for a week and it is now all dry and cracked
Best by/use by days are very conservative because they have to think about all the ways people will leave food standing around in warm atmospheres for hours before putting them in a fridge, or not at all etc etc.
Foods like cheese, ham, etc are the result of methods developed of preserving foodstuffs for long periods before fridges and freezers. Look at the premium you pay for a fully aged mature cheddar. Hams used to be hung in chimneys for a year or more before finally being eaten.
There have even been articles in the papers where reporters have experimented with how long food will actually last after opening before the flavour or texture changes. This has got nothing to do whether the food is safe to eat, there was no question of the reporters eating food that might make them ill. Some of the food they experimented with was good to eat weeks after the sellby/best by date.
I am hyper careful with chicken, pork, offal and fish, especially shellfish, but everything else, especially dry or tinned/packaged food kept on the ambiant shelves. I use my nose, mouth, eyes and, where appropriate, cook food well before eating - so 2 peole, no food waste.
I have just had my breakfast; cheese on toast and fruit juice. The cheese has been in the fridge for over a week and the fruit juice for 5 days. Both showing no deterioration in frshness, texture or flavour.