No sugar= no sugared sodas, cookies, sugared cereals, cakes, pies, donuts, etc.

Eating carefully is lean meats, seafood, chicken, salmon, eggs, (hardboiled eggs are easy).
veggies, greens (salads). Some fruit in moderation. (Bananas will make sugar as they brown up. So eating them overripe will have more sugar than when they are yellow).

You can buy pouches of Chicken of the Sea salmon...they are very convenient and a good source of protein and omega-3's.

You are 40 yrs old now and entering middle age. Your body is not the same as when you were 20. How it metabolizes food, has changed, and you need to change how you eat.

If you eat soups, read the labels unless you make your own.
MSG in processed foods stimulates the NMDA pain receptors, so people with nerve pain will feel worse when consuming that.
There are snacks now that are quite free of MSG... Lays makes a Corn Tostito, and potato chip with no MSG, now. (try to eat these in moderation however, as they are carbs and metabolize to sugar).