When I think about absolutely unavoidable costs, I think of food and shelter. To some degree, everything else is flexible compared to something to eat and somewhere to sleep. As I have previously described, there are other costs that are essentially mandatory here and now, but food and shelter are pretty much directly essential whereas things like gasoline and health insurance are more indirect.
As such, I want to address food costs first. Personally, I think while there certainly is inflation in food prices, I think most people both over-eat and over-pay for food. Regarding the former, it is fairly well-known that a lot of restaurant chains have been hiring food scientists for decades to make “hyper-palatable” food that leads to customers buying more. And while this food leads to folks eating more and wanting more, it is not fulfilling. As a result, eating it is like trying to fill a bottomless pit. Moreover, if you look at a photo of random people in the US from 1956 and compare it to people from 2026, the physical differences are severe. I’m completely in favor of not being mean to people because of their appearance, but “healthy at any size” is a deception. Being obese has numerous harmful health effects that are expensive to maintain.
In order to avoid spending money unnecessarily, it is important to avoid many food products, which are engineered specifically to encourage endless consumption. I personally try to avoid animal products altogether and sugar in excess. Both are associated with very calorie-dense foods that provide no benefit.
Recently, I have been getting food from farmer’s markets and local grocery stores. I eat only organic produce because I do not want to consume fertilizer and pesticides. Although organic produce often costs a little more, that cost is much less than prepared foods even from fast food restaurants. There is no vegetable company with lobbyists and food scientists, trying to extract more profits from, like, green peppers. In order to save a lot of money on food, I strongly recommend: eating all vegetables, prioritizing homemade food, and eating fewer calories.
I have done intermittent fasting for years: I used to fast for 16 hours per day and feast for 8 hours per day. Then, two years or so ago, I began to fast 20-21 hours per day. I would guess I eat around 1500-2000 calories per day, and that seems adequate. For many years, I thought I needed around 3000 calories per day, but I now think I was over-estimating my needs. While I admittedly exercise less now (and thus sweat out fewer calories), my suspicion is that I could have gotten away with less consumption.
As far as I can see, many people are addicted to excessive eating and also sedentary lifestyles. That combination leads to rising medical costs and unnecessary dependency, which will introduce other costs. Don’t do it! You have much more agency if you are able to exercise restraint, which begins with what goes into your body.