Is it dangerous to have sugar if you've been on keto?



I’ve been on keto for about 4 months. I read if you’ve been on a low carb diet like keto it can damage your circulatory system to have something that is high in sugar, is this true does anyone know?

I’m not planning on a binge or anything but would be nice to know if it’s a health risk to have a sudden sugar spike if you’ve not for a long time. Especially with Christmas coming up and the likelihood that i will have to eat a traditional lunch etc with my family.

Thanks for any help

(Allie) #2

I’m in my 7th (I think) year now and occasionally have something high sugar with less bad effects than I used to get before keto.

Where did you read this?


Thanks for reply

I can’t remember the exact article but there are several i’ve just found now

(bulkbiker) #4

Just goes to show if one 75g of glucose drink causes damage then imagine the damage that taking that amount (or more) in every single day could be doing!
Why would it have anything to do with what they ate for 7 days before the test?

My take from it… avoid glucose as much as possible.


Well the way i understood it, is it’s the shock that does the damage due to your body not being used to it. But yes, i agree 75g of glucose is not doing you any good anyway.

(bulkbiker) #6

I’m sure that was entirely what the experiment was set up to show… however…


No, nothings changed other than the fact you’re probably more insulin sensitive to it now which is a good thing. Sugar isn’t battery acid, it’s not going to damage your circulatory system. Eat good tasting food and enjoy the holidays, just be on your game so you don’t wind up in a binge or anything.

(UsedToBeT2D) #8

Only danger is that you may not stop eating sugar.

(Old Baconian) #9

Table sugar, sucrose, is a disaccharide composed of a molecule of glucose and a molecule of fructose. When we eat it, an enzyme called sucrase cleaves the molecule into its components, which are metabolised separately. All cells in the body can metabolise glucose, but fructose can be handled only in the liver. Fructose, apart from lacking the immediate toxicity of ethanol, has otherwise a very similar effect on the body to that of ethanol; it is metabolised by the same metabolic pathway in the liver that handles ethanol, and therefore causes the same liver problems when consumed in any quantity. It also has the same effect on the brain’s reward center (the nucleus accumbens), so it is addictive to many people.

Elevated serum glucose, the result of eating table sugar or too much other carbohydrate, causes various other kinds of trouble. Excessive glucose in the blood stream, hyperglycaemia, causes damage and even death, so the body responds by secreting insulin to drive the excess out of the blood stream. This excess glucose gets shunted into muscles to be metabolised, or else is converted into fatty acids and stored in our adipose tissue. Excessive amounts of fructose overwhelm the liver’s metabolic pathway and are then handled in the liver by a process called de novo lipogenesis, which eventually leads to fatty liver disease, steatohepatitis, cirrhosis, and ultimately, death.

The rise in serum insulin caused by a spike in serum glucose brings its own problems. Not only does it stimulate systemic inflammation, but hyperinsulinaemia also interferes with the body’s ability to produce nitric oxide (NO), which is what keeps our arteries relaxed and flexible.

When someone eats a high-carb diet, these effects all accumulate, causing all kinds of chronic problems. I suspect that if a person has been eating a ketogenic diet long enough to reverse some of these problems, a sudden high dose of sugar could cause effects more noticeable than they were back in the days when that person was experiencing constant, ongoing damage. Whether on a ketogenic diet or on a regular high-carb diet, it is wise to avoid sugar, because of the double-whammy it gives the body. Excess glucose is bad enough, but excessive fructose causes even more serious problems.

(Hyperbole- best thing in the universe!) #10

I’m trying to remember where I heard a trick to deal with special occasion eating… Megan Ramos! In an interview she said her tactic at a big family meal was to start with fat and protein. I can’t remember which first, but they often come together anyway. I think meat first, then veggies, then lastly breads and dessert. Even if she ended up eating the same amounts as she otherwise would have, the carbs didn’t hit her so bad. And honestly, she found she just didn’t eat as many potatoes and sweet things that way naturally.


Thanks for all the replies, very helpful.


I experienced a different method does good to me. If I eat sugar, I immediately must eat fatty protein. I can’t even not to, I DESIRE it like crazy. If I do that, I feel no ill effect (except something super subtle. I always feel I ate more than minimal carbs but I don’t feel unwell, uncomfortable or anything if I eat lots of fatty protein right after). But if I don’t do it… A small amount of fruit can feel bad. I had that with grapes.

Eating fatty protein before is probably good too but I never wanted sweets before normal food. I start with fatty protein :slight_smile:
And it’s logical we should get satiated with good food first, at least close to satiation. It’s another matter that many of us with a separate dessert stomach can easily eat a lot of dessert after becoming very full with normal food… If the dessert is carby, it makes me hungry (it doesn’t matter I was very satiated 10 minutes before, carbs do that) and I need to eat a big amount of fatty protein again. At least it happened before.

As for the original question, I am quite sure it’s not that bad. Shock may happen (it’s logical to me, our body does its business in ketosis and suddenly lots of sugar… nope, I don’t do that if possible) but we should feel that. Some people have very serious problems when they break keto with a lot of sugar. Some has problems with a little amount. And many of us are fine enough unless we do something very extreme. I probably would suffer if I dropped high-fat but I clinged to that all my life especially on high-carb. Fat and protein mitigate the carb problem, at least in my case, I very strongly feel it and indeed, it helps.
I can’t imagine that simply adding carbs would surreptiously shock our body and damage it… Mine surely would show signs right away. It is good at that. And we know people often feel something bad when suddenly eating much carbs.


Yeah that “study” was so bad. It is not dangerous but I can feel a sugar buzz when I do.


I was on keto for about 7 months before I had anything high in sugar. Even then it was a lower sugar ice cream. It was delicious. No noticeable issues right away but I was on vacation and started to slip. The most immediate result was swelling in my hands and feet (which I considered to be a normal part of my pre keto life). Now I take a carb meal once a month for birthdays or holidays and then immediately stop. I have read some people can’t stop once the gates of carb land have been opened. Figure out which you are before you get started so that you have a plan to get back on track. For me, planning that meal with the family is helpful to staying on track. Not necessarily as a reward but as a way of not getting down on myself and spiraling into negativity because I somehow let myself down. For me, that would lead to continuing poor eating habits more so than one carb meal approximately once a month.

(alex) #15

As I understood it was 9 people on a super dose glucose. Where one person had a huge spike or something. That messed the whole result up.

I found this video:

And here is the study:

(Allie) #16

Seems like a study that was set up to fail and create bad press.


Awesome information, thanks. Yeah i envisage staying on low carb but there will be some times like christmas i just dont’ want to and want to enjoy myself, i can stop instantly the next day - i def never see me changing from OMAD that really is awesome


Thanks Ardean. Yeah i never really had that much of a sweet tooth tbh, its more carbs like bread, rice, nachos, potato products, pasta etc i miss. I really like italian food and can’t stand thinks like zoodles or cauliflower lol. So those things i sometimes wish i could have, but saying that i’m fine really i don’t think about it that much and i do feel loads better. So all good. I occasionally have some 85% cocoa chocolate, a few squares in the evening with a coffee and cream :slight_smile:


Is it dangerous? to you? we are all different.

I am zero carb eater for heading into year 4 and if I go all in with eating carbs and dessert on a day I might end up on the hosp. sick as crap cause I did it a few years back and OMG I was so icky, and horrible, and shaky and ugh.

but will one carb meal ‘be dangerous to you’…eat it and find out.

remember sugar rots circulatory systems and weakens vessels but like Paul said, years of this damage accumulate etc. but ‘can that dessert’ take action in your body against your veins and more some, sure it can…you just don’t feel the damage. Is it a dangerous game changer one high carb sugar meal? probably not to death levels LOL

I mean sugar ruins the insides. Rots the body from the inside out…even this little info about having sugar issues like this: Diabetes causes high blood sugar levels, which can lead to the weakening of the blood vessels. In turn, the venous system is more susceptible to infection. Because blood vessels and veins are prone to inflammation and weakness, there is an increased risk of circulatory issues for those diagnosed with diabetes, including an increased risk for infection .

------so if all that is true with ongoing high sugar issues then that one carb sugar foods you have for a day or 2? or whatever, yea IS effecting your body on some level, you just don’t know it. One doesn’t need to be diagnosed with diabetes at all to be having sugar wreck and rot their insides.

And like KetoType2 said…then if you eat it will ya binge out more and crave and go off plan? that again is a personal situation for the individual. Some one bite is a train wreck and others can do a meal off and come back easily…so just know you on all this :slight_smile:


For me the danger is psychological and a slippery slope. Stand fast.