[Evgeny]

if you ate 0 grams of sugar for more than a couple of weeks you would die

No you absolutely would not. Your body can synthesize glucose from protein and fat, you can survive indefinitely on zero sugar. This is called ketogenic diet.

[reitanqild]

+1

IIRC both combat divers and people with certain kinds of epilepsy benefit from carb free diets as it reduces risk of passing out (for combat divers with rebreathers) and epileptic attacks (for epileptics).

[craftyguy]

What do you think a 'carb free' diet excludes? What does it include? I'm asking, because I'm genuinely confused by the fact that all plant (veggies, fruits, seeds/grains, all of it) matter contains sugars. Do a lot of folks really sustain themselves on meat alone? Hell, not even my 100lb german shepherd can live on only meat (IIRC carnivores frequently eat stomach contents of herbivores they kill/find to get nutrients [hint: it would include sugars])

[ruminasean]

I am vegetarian on a very low carb diet. No fruit, no high starch vegetables. It is possible to eat zero added sugar and almost zero natural sugar. As mentioned above your body can synthesize glucose from protein, to the extent that on a keto diet you must be sure not to consume too much protein, lest your body convert it to glucose.

[gojomo]

A carb-free diet eliminates plant sugars as well, yes. Many survive & thrive on meat alone.

[craftyguy]

Considering that many essential nutrients are provided by plants which also provide sugars, you'd have to eat synthetic 'food' in order to avoid all sugars.

[dualogy]

> Considering that many essential nutrients are provided by plants

None that I can think of that are proven "essential" in the absence of all carbs. "Phytonutrients" aren't proven essential. Vitamin C ("ascorbic acid") is 100% inessential & optional in the presence of plenty of the (actually essential) ascorbic molecules that are all furnished by fresh meat, including carnitine, creatine etc.

For homo sapiens, there is no essential carbohydrate and no essential plant food. Something to chew on!

[dualogy]

Late edit: of course none of this disputes or negates "that many essential nutrients are provided by plants" --- many indeed are. Just none that are essential that aren't furnished in sufficient amounts in a sizable helping of fresh-fatty-mammal-meat =) but the parent didn't even say "only by plants" so not sure why I reacted as if he did

[Evgeny]

I guess technically you are right, even meat has some carbs in it because muscles hold some glycogen.

The closest thing I can quote is the experiment that Vilhjalmur_Stefansson and Karsten Anderson took part in, eating only meat for a few years

https://en.wikipedia.org/wiki/Vilhjalmur_Stefansson#Low-carb...

http://inhumanexperiment.blogspot.com.cy/2009/09/two-brave-m...

In the end, the one-year project stretched to four years, during which time the two men ate only the meat they could kill and the fish they could catch in the Canadian Arctic. Neither of the two men suffered any adverse after-effects from their four-year experiment. It was evident to Stefansson, as it had been to William Banting, that the body could function perfectly well, remain healthy, vigorous and slender if it used a diet in which as much food was eaten as the body required, only carbohydrate was restricted and the total number of calories was ignored.

[dualogy]

> I guess technically you are right, even meat has some carbs in it because muscles hold some glycogen

Near-zero because muscle glycogen is used up upon death in a process called "rigor mortis" (not the case for liver glycogen however AFAIK). The fatty marbling luckily remains.