Not to be a dick, but it sounds like you actually just drank a can of placebo. Sugar intake isn't correlated with increased heart rate or inattentiveness in healthy people. The myth of the sugar rush can likely be attributed to confirmation bias [1], and you probably just extrapolated this onto your current experience.

Of course, you could just have undiagnosed diabetes too.

[1] http://www.yalescientific.org/2010/09/mythbusters-does-sugar...

Keep in mind that for many of us, including sciency types like me, just beliving something causes side effects can cause real measurable symptoms.

I had really annoying side effects from medication until at one point I realized I got the same side effects almost like clockwork even when I had forgotten to take it. At that point the side effects just disappeared completely I haven't seen them since.

(That said, the effect you felt might be real or not but I still agree with you that cutting back on sugar is smart.)

If you were actually in a state of ketosis for 3 weeks your body would have mostly adapted to it. It takes a couple days of carb refeeding for insulin sensitivity to return to normal.

http://high-fat-nutrition.blogspot.com/2007/10/physiological... < blog on the topic (sorry to link this blog again, he really has some good posts on topics like this with research linked in)

Again anecdotal, but I've had a similar experience. I've been trying to reduce the amount of refined sugars in my diet, with the aim of being completely off refined sugars/artificial sweeteners at some point this year.

I've been eating mostly just fruit for dessert after dinner. It's really good because after dinner is one of my sweet tooth triggers. Well I got the dumb idea to eat a piece of a chocolate turtle candy instead and within 5 minutes was sweating and my heart was racing. I had the lightheadedness too. I felt awful. On the plus side like you said this kind of experience helps me not want to eat it more.

I started an open facebook group with a few friends so we support each other in not eating it. It's been super helpful too to have someone help keep you accountable. It's pretty new but if anyone wants to join feel free: https://www.facebook.com/groups/1411638028861122/

Edit: A lot of the reasoning behind quitting can be found in this lecture by Robert H. Lustig, MD, UCSF Professor of Pediatrics in the Division of Endocrinology titled "The Bitter Truth". https://www.youtube.com/watch?v=dBnniua6-oM&t=1s This, in addition to a lot of reading about world history of sugar trade and how disease is usually right behind the introduction of sugar is a large part of my personal decision to try to stop eating it.

Have one every month. That way it is not a temptation and you do not make a big deal out of it.

I'm a diet coke addict and the way I deal with it is that I drink half a bottle and keep the rest for latter. The fact that I know that I still have a half-full soda makes me not want to buy another. And if I feel like drinking some soda I just take a sip. The soda is at room temperature so it tastes like shit. This crappy taste makes not want to drink anymore and I can go without buying a new bottle of diet coke for more than a week. Sometimes I can last a month. By using this method I don't feel guilty if every once in a while I have a soda and I've been able to reduce my daily intake of a bottle of soda to just one small bottle (20FL oz) every one or two weeks.

When (mostly) quitting soda I discovered my craving was actually 80/20 carbonation/sweetness, so I could almost totally satisfy it with club soda (cheap) or sparkling mineral water (pricier but generally better). Seltzer didn't work—I think it had too little salt, tasted weird. Lemons and limes are pretty cheap if you want a little flavor and a touch of sweetness, and they provide some vitamins so they're not a total waste of calories. Much better than various flavored sparkling waters, IMO. Mostly I drank it plain, though.

Of course I have a lot more fat on me now than back when I averaged (guessing) 1.5L/day of soda and probably 4000+ total calories a day, almost all junk food. Lots of effort just to slow the progression away from a fit (looking) body toward a middle-aged one. And I feel way, way less healthy and get sick all the time, as opposed to never. Man, being a teenager was great. :-/

While I personally think low carb is the way to go, you are missing a thing here - body adapts to the staff it does every day. If you don't eat fat at all, and then you get a lot of it, you will probably feel ill. THe correct way would be to introduce a sugar over a period of time.

Have you considered those symptoms are more commonly associated with caffeine which is also found in Sprite? Sounds like your tolerance may have lowered.

Edit: I stand corrected, Sprite does not have caffeine

Sprite doesn't contain caffeine