However, I could eat ten apples over the course of a day and wash it all down with a quart of orange juice, taking in ~200 grams of naturally occurring sugar without eating any added sugar whatsoever. Despite its adherence to the above recommendation, this is probably not healthy.
Are there recommendations out there for how much total sugar (whether naturally occurring, or added during processing) is too much in a person’s daily diet?
I hope not because - as you’ve already shown - they would be meaningless and misreading.
You can’t abstract numbers out in this fashion. Calories and sugar have to be placed in the context of overall diet. Empty calories are empty calories. They should be avoided, but if you do eat some they aren’t innately harmful. But excess calories, even if eaten in “good” foods, are still excess.
It all comes back to eating sensibly and moderately. Everything else is confusing complication.
The FDA recommends about 300 g carbohydrates each day for a 2000 calorie diet, and recommends at least 25 g be dietary fiber (obviously how many of your calories should come from carbs is somewhat controversialm but you asked for any recommendation). From a dietary perspective, there’s not all that much difference between eating sugar vs. any other simple carbohydrate. Most things that have fiber also have some simple carbohydrates, so it’s not as simple as saying you can eat 275 g of sugar per day, but that’s a ballpark figure from one group.
There’s no need to eat any sugar at all. Then again, it would be stupid to forego eating fruit because it has sugar. Also, if you like sugary stuff such as cookies, there’s no reason you couldn’t eat some once in a while.
Sugar isn’t great for your teeth, but otherwise there’s no much difference between eating sugar or eating simple starch, as the latter is decomposed into glucose rapidly once you eat it (this starts while you’re still chewing). And it’s not like eating too much fat or eating too much protein is a great idea.
The idea of warnings against “added sugar” is that sugar is usually added separately from other nutrients.
If you did get all of your daily sugar from oranges, here are the nutrition facts. So an orange is about 4% daily value of sugar, so you’d need to eat 25 of them to hit the “limit” recomended by doctors. It’s got 3% daily value of protein, so you’ve satisfied 75% of your protein needs; not ideal, but not bad either. You’re at like 4000% of Vitamin C, and hitting targets for many other vitamins. You’re at 425% the recommended fiber, so you’re going to be really regular!
But if you eat orange-flavored, sugar-added artificial drink, then you get nothing but what the manufacturers decided to add. 100% of the daily value of sugar. You might get no nutrients whatsoever except for the sugar.
Glucose is the basic energy source of the body. Without glucose, the body would quickly grind to a halt. So glucose as a critical endpoint of metabolism is true.
But not entirely. Fats break down into fatty acids, which then are further converted into a variety of products for energy production and storage. They react to glucose levels in the blood, but don’t break down into glucose themselves. Proteins break down into amino acids, some of which are stored and can be converted into glucose if necessary. However, that doesn’t mean that all proteins metabolize as glucose.
That’s highly oversimplfied, but the important point is that the body is really complicated and lots of different pathways are involved. Which is also why trying to concentrate on one single nutrient to the exclusion of the complexity of the diet is counterproductive.