There are quite a few of my super fruits that can only be found in cans that are loaded with syrup. Such as Jackfruit and Lychees. Lately I have been throwing away the syrup and pouring the contents into boiling water for a few seconds before eating them.

My question is whether this is enough to get rid of the sugar residue on the fruits or is the syrup absorbed beyond the outer layer? If so is there another way of getting rid of the excess sugar? I would make life much easier.

it is up to you entirely

My guess is there is bound to be some sugar that is absorbed into the fruit if it is canned in sugar syrup.  Of course, you are decreasing that sugar by rinsing in hot water.  

You must decide your level of compliance.  I won't eat any sugar at all because that is necessary for the level of wellness I like to maintain, but others may have different standards.

With Jackfuit and Lychees you may be able to get them dried instead of in cans (I have bought both this way).

As you observed the fruits are nearly always packed in sugar syrup in the cans.

In season you should be able to get both fruits fresh. Especially in Asian markets.

A lot of times even dried fruits have added sugar. Like dried Filipino mangoes. I for one am not a purist. I do avoid sugar but if a little bit seeps into my system I am not too worried. I was mainly concerned about whether there would still be a high quantity of syrup in the fruit even after boiling.

Like having one or two small blocks of 85% Chocolate, that would still contain a certain amount of sugar. My guess is that the fruits after boiling would have less un natural sugar than the chocolate blocks.

I wash sweet canned fruit and the devil with the rest.. I do the best I can and that is good enough.. worry is what makes me sick..

enjoy and abserve any adverse reactions.. if you have no itching any where then it's about as ok as can be.. Itching can means that dead tissue is being discrded. or for me its a warning when my chin itches.. ever so slightly..

the rest is history.. remember dr D expects 80% compliance.. so would you be ok with that?  I am happy with 90-95% .. and mostly Beneficials or better..

I think the body needs some 'stuff' just to be healthy.. to clean and it reacts to much ..

my opinion..

Rinsing off the syrup is going to decrease the amount of sugar in the final product, but it won't be zero. Some of the sugar gets absorbed into the fruit and simply can't be removed.

It depends on your desired level of compliance, and also how sugar rates for you. As a non-secretor, I'm not supposed to have sugar at all. I don't eat 85% chocolate; I eat unsweetened baking chocolate. If something is canned with sugar, I don't buy it. If it's dried with sugar, I usually won't buy it; exceptions being dried mango and cranberries that I buy for DD2 but I don't even consider eating them myself. I'll admit to sometimes eating 1-3 chocolate chips.

You need to balance "avoiding sugar" with "wanting to eat these diamond fruits." For DD2, making sure she has some variety in her diet outweighs the negatives of some added sugar. For myself, I'll skip the fruits if I can't get them in a 100% compliant form. But then, I only get 1 small portion of fruit per day and I'd rather focus on diamond veggies. I can find dried prunes and figs easily enough, and I don't really get bored with my "lack of variety" in fruits when I eat so few of them.