Does type of sugar affect a ketogenic diet in any way?


(M) #1

Does the type of natural sugar found in nuts and veggies have any impact on a keto diet?
Some have more fructose, some are more sucrose, etc.


(Bacon is a many-splendoured thing) #2

The short answer is that yes, sugar affects the body quite considerably.

Table sugar, sucrose, is a disaccharide consisting of a glucose molecule bonded to a fructose molecule. It is the fructose that is responsible for the sweet taste.

Glucose is what carbohydrates are made of, and it is the main driver of insulin secretion, so it needs to be strictly limited if we want to keep our insulin level low enough to remain in ketosis and metabolise fats.

Fructose must be handled in the liver, and the pathway that handles it has a strictly limited capacity. (That same pathway also handles ethanol and branched-chain amino acids.) Exceed that capacity, and we develop fatty liver disease, then steatohepatitis, and eventually cirrhosis. Once the liver is too badly damaged, death is a distinct possibility. Fortunately, the liver is a highly resilient organ, and it takes a long time to damage it beyond repair.

If you want to learn more about the effects of fructose, watch the lecture entitled, “Sugar: The Bitter Truth,” by Dr. Robert Lustig. It is available in several incarnations on YouTube. There is also a later lecture, entitled, “Sugar 2.0,” that you might find interesting, as well.


#3

My answer is that different carbs affect the body differently. I believe if vegetables are eaten with meat/fowl/fish there is no significant insulin spike. If you ate a couple slices of processed bread, however, or a slice of pizza, a biscuit or a piece of cake, there would be an insulin spike and your body would likely know the difference.

Robert Lustig does believe (rightly so) that sugar causes diseases. But he is referring to processed food. He does not believe all carbs are equal. He recommends eating a variety of both vegetables and fruit, and thinks fiber is essential for health. His main focus is on the importance of eating nourishing whole foods. He recommends eating intact whole grains, eggs, meat, nuts and seeds, dairy, beans, fruit, vegetables.


#4

In my opinion, the effect of the sugar in the food consumed depends on the composition of the food.

For example, eggs have a bit of sugar. However the fat & protein in eggs greatly exceed the sugar content & makes it negligible.

If you eat a chicken thigh & some brocolli, the sugar in the brocolli makes a small percentage of the meal. The fat and fibre in the meal also slows down the impact of the sugar.

If you eat a pizza & some potato wedges, the sugar & starches in this meal greatly exceeds any fat, protein or fibre in the meal. The impact of the sugar and starch will be significant.

Unless of course maybe if you only ate one bite of the pizza & one bite of the potato wedges - in which case the quantity consumed means that the overall sugar/starch consumed is insignificant and unlikely to have a significant impact.

So, if eating a food item or meal, look at the composition and quantity of the food item or meal. Both will determine the impact of the sugar in that food item or meal, on the body.

Some other factors that should be considered as stated above is whether or not the food is processed. Sugars in processed foods seem to have a greater impact on the body as they are too readily absorbed, compared to the sugar in unprocessed foods.

The type of sugar also determines what aspect of the body it affects. So it is important to differentiate between glucose and fructose like Paul said above.


(Ohio ) #5

Oh ya. At least for me.
My personal maximums before I get are:
10g refined sugar or HFCS
15g cane sugar
25g maple syrup
50-100 raw honey

It’s my n=1.

I normally avoid most all carbs, except OMAD where it seems carbs slow my digestion. Makes me feel full longer.


(Eve) #6

What is n=1?


(KM) #7

Your personal experiment. N refers to sample size, so N=1 means just you doing you.


#8

Wow, you know these such accurately? I only have vague ideas but I am aware that (almost) pure sugars like honey are problematic even in 10g! My body doesn’t care about the origin, pure sugar isn’t its thing. (I absolutely adore good honey though, it’s THE tastiest thing to use to sweeten other things or life - though coconut sugar is close. But I adore almost all fruits as well while my body doesn’t like them but tolerate them in tiny occasional amounts.)

I have…
Some sugary horrible processed thing - any amount is a horrible idea.
(Almost) pure sugar, honey, coconut sugar, table sugar, doesn’t matter which: 5g alone is stretching, a bit more is fine when enough fat and protein is present. But even other, not sweet carbs would dilate the simple sugar, not ideal but better than trying to eat spoonfuls of honey :smiley: Oh I did that on my old high-carb times, I ate tons of honey, more than table sugar… My body knows better now.
Starches: I can handle pretty much though once I got sugar poisoned by 100g rice (raw weight)… Couldn’t test another time as it’s not my thing to eat 100g rice (400g boiled rice) all alone :smiley: It was tempting back then. Surely adding fatty protein helps but I always feel if I eat much carbs.

And carbs not counting towards net carbs and as far as I know, all animal carbs are irrelevant, I can handle any amount as far as I can eat the food without problems (I mean, 200g animal sugar would be a too serious overeating so I surely would feel bad but not due to the carbs, most probably. I admit I never had more than 50g sugar on carnivore and it probably will stay so unless I will be too curious one day… :wink: Or tempted to drink liters of milk on a hot summer day - better than beer! - as I have no chances to go really high without milk :smiley: I don’t care if it’s not proper on carnivore, it IS a carnivore item. And anyway, it would be to figure out if lactose in huge amounts would do anything bad to me. I definitely feel 5g honey but 40g lactose feels normal, I wonder about my limits. It IS sugar so maybe it would do something over my ketosis carb limit…? Not like I feel any different in and out of ketosis… I just feel the carbs but I don’t need to go out of ketosis for that.)


(Ohio ) #9

Rough estimates. Honey isn’t keto obviously but I find it useful to narrow the feeding window.


(M) #10

I never eat any processed sugar at all.

I was just wondering if perhaps certain natural sugars are more addicting. For example I had more trouble stopping macadamia nuts than walnuts.


(Ohio ) #11

Macadamia & Walnuts are more ketogenic than meat. Sure there are trace carbs, but the lack of protein aligns it better with legacy keto ratios.

You’re clearly eating very healthy if this is the avenue you are on.


(Bacon is a many-splendoured thing) #12

Now that seems like an odd statement, on the face of it. Too much protein may interfere with ketosis, but in the proper amount, and not accompanied with carbohydrate, it has very little effect on the body’s metabolic state. As per data from Benjamin Bikman, at any rate.


(Central Florida Bob ) #13

Do macadamia nuts have more carbs than walnuts? They have 4 grams total per ounce of nuts. Yeah, I weigh out a portion. At least 90% of the time. What do walnuts have?


(M) #14

Nutritional information doesn’t say they have more carbs, but yet it says they have more sugar.


(Central Florida Bob ) #15

I looked up both on the USDA nutrition site for 1 oz portions. Macadamia nuts have roughly 0.44 g more sucrose than walnuts, 1.13 grams vs. 0.69 grams. They both have essentially same amount of fructose and glucose, 20 milligrams. These are “legacy” measurements and the entry for walnuts has three digits shown, down to 1 mg while the other entry has two digits shown, down to 10 mg.

Personally, when I have any kind of nuts, I weigh the portion of 1 ounce, but my scale drifts a little during use and I don’t care enough to put a couple of pieces back in the can or bag if I see 1-1/4 ounce.

EDITED at 7:24 PM: I noticed slipped a decimal in the first line. Instead of 0.44 grams, I wrote 44 mg.
Sorry if anyone went with that.

Nutrition data from:
https://fdc.nal.usda.gov/