Fiber’s the new fad supplement.
While they're not essential in short-term survival, they're essential for long-term health:
https://www.ncbi.nlm.nih.gov/books/NBK559033/
We have enough peer-reviewed studies on this.
We’ve already known fruits and vegetables are healthy. Fiber is the reason why eating an orange is good, but drinking a glass of orange juice is about equivalent to a bottle of coke. That’s not an exaggeration, by the way, it’s about the same sugar content.
If you want to eat the recommended 35g of fiber a day, you won’t be able to reach it with just supplements. You need to be eating fruits and vegetables at every meal. For my entire life, everyone has been saying to eat fruits and vegetables at every meal in large quantities.
But the fiber does not survive. The fiber alone is what makes the sugar intake okay - fiber slows and prevents blood sugar spikes, which, over time, is what causes insulin resistance and then diabetes. Drinking orange juice is diabetes fodder. Again, it’s basically soda. Eating oranges doesn’t have that effect because of the fiber.
Also, another note on vitamins: for most vitamins, once you get enough, the rest is wasted. It’s not like eating more vitamin C gives you more and more benefits. No, your body has an amount it needs, which is quite low. Past that, you pass it in urine. The amount you need you reach every day with no effort.
And, additional vitamins still have to be metabolized in the liver and go through the kidneys. Too much vitamin intake is damaging, many doctors can tell you stories of acute liver failure as a result of excessive vitamin intake. It’s basically impossible to do that via food. But when you see those vitamin supplements that are like “2000% daily value” - yeah, don’t take those. You’re not getting any benefit.
The US had for a long time a much too low recommendation of around 0.8 g of protein per kilogram of body weight per day.
That has been discredited by various studies. It is an amount that is sufficient to keep you alive, but it is not sufficient to keep you in good health until an old age.
It is not known with any certainty which is the optimum amount of protein intake. On certain lab animals protein restriction lengthens life, but for now there is no evidence that this also works for humans. Too much protein is known with certainty to be harmful for humans.
I believe that it is likely that the optimum protein intake is somewhere between 1.2 and 1.5 grams of protein per day and per kilogram of body weight, for a person with no overweight. For an overweight person, the protein needs do not increase proportionally to the total mass, i.e. the extra fat does not need much protein.
I wonder whether the so low protein recommendation of USA was actually intended for average Americans, which are likely to be overweight, in which case that number might provide an adequate protein intake.