Re: Jeff Nippard's follow up video on Sugar

Jeff Nippard recently posted a video "busting" the "myth" that Sugar is harmful / making us fat. I posted a comment on the vid to explain why his points fall short and made a Patreon post about it.
Just recently he posted a follow up video addressing some of the comments that refuted what he was saying (Thanks to David for letting me know).

Here's my response to that second video:

"Hey Jeff, glad to see a follow up video… but it still feels quite lacking and I don’t think you’ve successfully defended your conclusion on sugar. (For anyone reading, let me point out that I do like Jeff’s channel and his other content - Just not a fan of his stance on this particular topic)

■Insulin
You mentioned a couple things, but I’m gonna jump to insulin sensitivity, because this is the big point. Fructose (as found in sucrose, table sugar) has unique effects on insulin signalling. Yes, protein or other things will give you an insulin rise, but fructose directly hampers insulin sensitivity. 

If you’re not familiar with the biochemistry, Dr. Jason Fung’s post titled “Fructose causes insulin resistance,” explains the situation well. One study he points to called “Impaired cellular insulin binding and insulin sensitivity induced by high-fructose feeding in normal subjects” shows that insulin tolerance is 25% worse when you add 1000kcal of fructose to diet compared to adding 1000kcal of glucose. 

The eucaloric study you point out at 10:40 (Black RN et al.) as showing that sucrose does not worsen insulin sensitivity, which by the way, in the acknowledgements section says “This study was supported by an unrestricted research grant from The Sugar Bureau and Suikerstichting, the Netherlands.” Shows on page 3570 that fasting serum insulin is higher with sucrose (9.6 on 25% sucrose diet, 8.6 on 10% sucrose diet). LDL cholesterol and triglycerides are also higher on the 25% sucrose diet… 

If you’re curious about the mechanism: as I mentioned in my comment on your other video… during fructose metabolism, insulin receptor IRS-1 is serine phosphorylated, and serine IRS-1 is inactive = insulin resistance. (Exercise can ameliorate the fructose induced insulin resistance as you suggested, but this is beside the point)

■Sugar and Fat Production in the Liver

Despite what Brad Dieter says in the podcast you linked to, Yes, Fructose does promote more calories getting turned into fat. 

-Look at “Regulation of Hepatic De Novo Lipogenesis” by Hellerstein et al pg 538: The Fractional De Novo Lipogenesis, i.e. "New Fat Making” rose markedly (32%) when people were given Fructose compared to glucose. (1%) 

-See Parks et al. J Nutr 2008 - Acute administration of fructose raises triglycerides.

-See Faeh and Schwarz Diabetes 2005 - 6 days of high fructose feeding: Triglycerides doubled , de novo lipogenesis up 5x and free fatty acids doubled. ( free fatty acids - another way fructose promotes insulin resistance). That’s in only six days  

■Sugar not being addictiveLet me first say that I think sugar is addictive, but of course not to the degree of something like heroin or cocaine. That headline saying sugar is 8 times as addictive as cocaine has a misplaced definition of addictiveness. 

You pointed to two things:
(1)7:23 Rodents with taste buds knocked out don’t over eat

-This isn’t a surprise considering a huge factor in the enjoyment of the sugar is stripped out. I wouldn’t be surprised if taste was a big factor in getting the dopamine rise from sugar (fructose). (Chapter 6 of "Neurobiology taste and reward" by Katz and Sadacca explains that tastes activate the nucleus accumbens) Cut out taste buds, no dopamine, no addiction. There are several pathways to get a dopamine rise/effect from something other than ingestion smoke, snort, inject and in the mouth - think chewing tobacco - users just have it tucked in their lip and get their fix that way. People using nootropics may be familiar with the fact that with some nootropics, you can get a longer “boost” by just having it sit under your tongue. (More simply: Who’s going to get hooked on sodas if they can’t taste them?)

-Not a foundational argument but: if it was all about taste, why aren’t we hooked on say… really tasty meats? I found this restaurant last month that made the best spare ribs I’ve ever had and I proceeded to have them every day for a week, then …I just forgot about them. Someone “hooked” on sugar - they will not forget to eat sugar. 

(2)7:37 Devaluation experiments on rodents (added an agent to the sucrose that makes them throw up)

-This isn’t very convincing considering the “reward” from heroin or cocaine is massive compared to throwing up. Throwing up isn’t much of a deterrent to getting high AF. Sugar gives you a small high that can be repeated frequently (and this frequency is part of the appeal), so it’s really not worth going through vomiting for. I bet if you did a similar devaluation study with tobacco, you’d see that people (or rats) aren’t going to puke just to get a puff of a cigarette. 

-Actually …there are people who continue to consume fructose despite it making them sick - Look up the inuit who have fructose intolerance: They will continue to consume fructose (in quite high quantities) despite the gastrointestinal distress it causes them.