From what I can determine, and I've had this debate with friends ad nauseam without resolution, all things being equal- the body does not really care what you feed it.
If we concede that a 2000calorie diet is about right, and you consume 2000 calories of pure sugar, supplemented with all the macro nutrients needed to keep the brain firing, then you'll be ok. Your stomach on the other hand will not thank you. nor will your plumber.
It's a fine balance between what is 'needed' and what is 'good'. People say that to lose weight, you must not consume any fats. Relating fats in foods with fat in... you. I disagree, but I don't expect to change anyones mind.
What I can tell you, is that I once lost 40 pounds while dieting. And the diet consisted of a strict 1300 calorie per day regime, created from a carefully measured balance of pizza and red wine. And a multi vitamin. Not "healthy" but not fat free either, and it worked.
Anyway, I digress. IMHO the level of sugar in Jake is nothing to worry about. But if you are concerned, there are plenty of alternatives out there. I chose Jake after evaluating many other products for taste/consistency/availability/price/convenience and it won. Soylent is not available in my country but I tried it for 2 weeks and at the time it would have won, but it lost points due to the whole not being able to actually buy it thing.
Take the ingredients list to your physician and ask their opinion, although when I tried this after being on it for 3 months and asking them to take a full spectrum blood test, they basically told me I was crazy, and what's wrong with a carrot anyway. So your mileage may vary.