Even simpler if just looking after oneself: keep the receipts, make the accounting YEARLY.
I have a whole food, plant-based diet and I cook all my own food. I don't buy any processed food, anything with anything animal in it, refined sugar, refined oils (except olive oil for the air fryer), refined carbohydrates, things preserved with salt/vinegar/oil or any stimulants. For B12 I eat Marmite (UK). Most of what I eat is that rare thing: fresh vegetables.
Because I eat almost everything (sometimes there are bad apples), I throw very little away and that includes packaging too, where I am surprised at how little that amounts to. I have a small box for recycling and I only have to empty it ever two to three months.
I could cheat and not keep the receipt on a huge box of chocolates, beer and biscuits but I would only be fooling myself.
As for bread, I just buy flour and yeast, to put it in the breadmaking machine. I buy wholemeal flour which is white flour with some of the stripped off parts of the wheat thrown back in. I am happy with that compromise as it makes a very nice loaf.
Apart from Marmite, nothing I buy has much of an ingredients label, a cauliflower is a cauliflower and has no ingredients.
The receipts are my way of accounting, I could look at them all for the last year and buy everything I need that is shelf-stable for the year ahead.
Mayonnaise used to be something I did eat a lot of, but now that is on the banned list, and I have no idea why I would ever want to eat that stuff nowadays.
I eat to satiety and beyond, my physical activity consists of walking/cycling and I am fitter than I have ever been with a digestive tract that is rock solid. Bloating, constipation or the runs are alien conditions to me, I also get a 'long range bladder' into the deal.
I don't count calories, my goal is to get as many as possible from just vegetables, beans, legumes, nuts, grains and fruit. I love cooking and my 'self care' routine. Since there are seasons, my food always changes, right now spring greens are floating my boat.
The idea of keeping the receipts is to have all of them with no banned items in them, and also to track my nutrition experiments. At the moment I am trying to do a year long streak of 'an apple a day' to see what that is about.
Regarding counting macronutrients, why bother? Nobody counts fibre, which is crucial for the lower gut, with protein we eat 2x in the West and nobody is counting phytochemicals in plants beyond the 'five a day' thing. With the exception of bread, everything I eat counts towards the 'five a day' so I am probably on twenty portions of fruit or veg a day, not that I am counting.
I don't mind people wanting to diet to fit into a dress for a special event, that is something that works for them, albeit with yoyoing. I want to be at my fittest during the summer months, to go cycling, and, during winter, I don't care. In this way I am embracing yoyoing, however, my weight does not go up over winter, I just lose some muscle, to get it back again during spring.