If an insulin spike still happens, it will cause a "sugar crash", which will typically drive extra consumption even if the original source was calorie free.
D-Glucose. If you find a microbe with the ability to metabolize
L-Glucose it'll be big news, and most likely an alien.
"An L-glucose catabolic pathway in Paracoccus species 43P" https://pubmed.ncbi.nlm.nih.gov/23038265/
But it's true the vast vast majority of life on earth cannot metabolize L-glucose and it would be unlikely to have bacteria in your gut capable of metabolizing it.
This extra water then causes the laxative effect.
"Hey! This version of cocaine makes you still feel hungry!"
However, there's a new synthesis method available. Could have startup potential.
"Stop stuffing your face" will, causally, prevent obesity. "Stop having sex" and "don't take drugs" will, causally, prevent unplanned pregnancies and drug addictions, too. But thousands of years of human behaviour show that these are not effective policies because humans will never follow them. Thinking otherwise is simply delusional.
The sugar debate is really fascinating, too, because it's a clash of two diametrically opposed philosophies.
On the one hand, it's something demonstrably "bad" that humans (on average) demonstrably cannot control themselves from consuming.
On the other, it's something that a lot of people find really enjoyable. Who are we to dictate the life priorities of our neighbours? Just because I think living like a monk is worth an extra decade of life doesn't mean someone else does.
I'm gradually settling on the view that these substances should be sufficiently taxed to pay for the associated healthcare costs, but no more. Personally, I feel that those taxes should also subsidise healthier foods (at least for low-income individuals families), but that may be a harder sell.
When my tax dollars go towards a health care system that pays for some medication, medical consultations, and surgeries, I think it's fair to say the choice of what one eats affects everyone. It's one thing to get an unforeseeable disease, it's another to live a particular lifecycle that we know is conducive to long term health problems.
As you touched upon in your closing paragraph, I would prefer taxing these items or subsidizing healthier options.
If you're really healthy you live to 95 after retiring at 65, taking out social security and medicare for 30 years. And spending the last 10 with alzheimer's basically in full time care.
If you eat like shit you have a heart attack at 57 and die before taking a dime out of medicare or social security.
Do people in the UK, Aus, Canada, France etc engage in more unhealthy activities because they have access to good healthcare? And I would say the observed answer is no, the population doesn't engage in more risky behaviour.
And you pay for healthcare anyway to cover emergency rooms that have to serve everyone so hospitals don't all go bankrupt. And then that cost gets put back on the insured... who have their employer pick a plan for them... who then have insurance middle men nickle and dime doctors to give imperfect, but cheap treatments. Or doctors just try to do lots of tests/imaging because they know the insurance will cover it.
Not having universal healthcare is truly the worst of all worlds. There's no benefit to it unless you are an investor, in the insurance industry or are rich enough to not care about the public at large.
Obviously there will always be some proportion of people who draw from the system without ever paying anything in taxes (i.e. long-term unemployed). That's the case with any form of welfare, though. If you're philosophically opposed to non-net-taxpayers deriving any form of government benefit, then I'm assuming you're a priori opposed to universal healthcare.
Even if there is a correlation it doesn't mean it's out of hand.
Japan has very low rates esp. compared to the other nations around it's 'obesity rankings' 
We don't need that much sugar.
Additionally it's cultural: not all western countries have such rampant obesity. Smoking is no longer cool, and so on.
As our 'cup runneth over' with every material thing that suits our fancy (sugar, information, 'cheap stuff', addictive substances (like oxycontin, fentanyl), even porn) we have no choice but to try to have more self control.
Randy Marsh I think said it best  "We must only use the internet only for what is necessary, no browsing while watching TV ... and for porn twice a day, max".
The 'Big 5' trait closely associated with this is 'Conscientiousness' and it's the trait mostly clearly correlated with positive life outcomes of every kind: better performance in the workplace, lower rates of incarceration, more wealth, happiness etc. etc..
But if we can find a non-toxic substance to 'help out' wit this then that's good too - though I always wonder about the viability of eating non-natural chemicals. It seems both Sucralose, Aspartame are not without controversy.
So kudos on these researchers, but it may be a long time before we can fathom how safe it is.
Although, I think in this case it is required because it's high time.
Disclosure: we’re an investor in Stem Sugar (YC-18)
Easiest to avoid eating added sugars and saccharine sweetnesa than to try to engineer something that might have its own set of side effects.
Azad MB, Abou-Setta AM, Chauhan BF, Rabbani R, Lys J, Copstein L, Mann A, Jeyaraman MM, Reid AE, Fiander M, MacKay DS, McGavock J, Wicklow B, Zarychanski R. Nonnutritive sweeteners and cardiometabolic health: a systematic review and meta-analysis of randomized controlled trials and prospective cohort studies. CMAJ. 2017 Jul 17;189(28):E929-E939. doi: 10.1503/cmaj.161390. PMID: 28716847; PMCID: PMC5515645.
Sugar is already tricking our biology. It brought us a diabetes pandemic. It is weird to say that it is difficult to get worse, but looks inevitable if we are using scientists to create more sugar in place of fixing the issues the overconsumption of it already created.
There's no trick involved. Sugar appears to be exactly what it is. You want to eat it because it's sugar; that's your biology functioning as intended.