Cut Sugar/reduced Carbs - Huge energy increase then huge decrease


About 7 months ago I decided to cut out things like sugar, seed oils, and a lot of carbs. I am not at keto level of carbs.

The first couple weeks my energy levels were unlike anything I have had in my life. For once I could concentrate on reading and retain the information. I was excited to start work for the day and had more focused hours than ever.

Then after those two weeks there was a pretty sharp decline in energy, then steady decrease to now.

At first I thought maybe since I’m low carb but not quite low enough to be keto I’m starving my brain of glucose so I added some carbs to my breakfast. This helped a little bit. IIRC, at that time I was feeling somewhat detached, then adding a whole grain tortilla and potatoes to my sausage and eggs made me feel a bit more present, but the low energy remained.

Has anyone else experienced or seen anything like this before? I’d love to get back to those first two weeks because they were incredible.

Thank for any help.

Additional information that might get asked about:
Male, 6’, 162 lbs, desk jockey for work, but pretty active for exercise and labor around the house.
<5 g of added sugar a day
80-120g of carbs a day
probably 2600 calories a day, 3000 before all this.
Eating window of 10:30AM - 8:30 PM. Only water and electrolyte pill between waking and breakfast.

(May the blessing of bacon be always with you) #2

Welcome to the Ketogenic Forums!

The two main sources of the body’s energy are glucose (carbohydrate) and fatty acids (fat). Because of the bad effects of excessive glucose (hyperglycaemia) on the body, insulin is mobilised to get it out of the blood and safely into muscle (to be metabolised) or into fat tissue (to be stored). Under low-carb conditions, the body signals the liver to make just enough glucose for the cells that need it (there is usually 1.0 U.S. teaspoon circulating in the blood at any given time) and uses the fat in the diet (and any excess in storage) to produce ketone bodies. Although we enter ketosis within a day or so after cutting our carb intake, f we have been eating too much carbohydrate for any length of time, the skeletal muscles will need to re-adapt to metabolising fatty acids and to heal the damage from metabolising too much glucose, which normally takes somewhere between six and eight weeks of a sufficiently low-carb diet. This latter process is called keto-adaptation, or fat-adaptation.

Failing to give the body an adequate supply of energy will result in fatigue, lethargy, a sensation of cold, and so forth. The body does not normally metabolise protein for energy, preferring to use the amino acids from dietary protein to repair and rebuild tissues, but it can rob proteins from tissues and make glucose out of them—although this process carries a heavy energy cost, so the net yield is much lower than the yield from fats or glucose. So it’s the body’s equivalent of burning the furniture when the wood pile runs out.

How little carbohydrate one needs to eat depends on one’s degree of insulin-resistance. A perfectly insulin-sensitive person secretes reasonable amount of insulin in response to dietary carbohydrate, and such a person may be able to eat, say, 100 g/day and still keep insulin low enough to be in ketosis. A highly insulin-resistant person may find that his or her response to even 20 g/day of carbohydrate is enough insulin to keep him or her out of ketosis. It all depends.

The insulin response to dietary fat is the bare minimum required for survival (some insulin is necessary, it’s an excessive amount that causes problems). Fat also does not cause metabolic damage, the way glucose does.

The insulin response to protein amplifies the response to dietary carbohydrate. A sufficiently low carb intake renders the insulin response to protein minimal (that is a simplification but is essentially true); when protein accompanies dietary carbohydrate above the ketogenic level (for that person), then there is a significant response to the protein as well as the carbohydrate.

We recommend a diet that avoids all sugar (not just because it is a carbohydrate, but for other health reasons, as well), all grains, starches, tubers, and legumes (since they are just glucose molecules arranged in various ways) and allows primarily leafy greens and cruciferous vegetables (because they also contain indigestible fibre that mitigates the digestible carb content). It also encourages a reasonable amount of protein, and advises eating fat to satiety (in other words, cook with butter, lard, tallow, or coconut oil, and don’t shy away from fatty cuts of meat and fish). The standard dietary advice from the government is almost exactly backwards, in terms of promoting metabolic health.

Not knowing your precise circumstances or current diet makes it hard to advise you. People on a well-formulated ketogenic diet have eaten 3000-5000 calories a day and still shed excess fat. People on a well-formulated ketogenic diet who have stinted the calories have found their bodies surprisingly reluctant to shed fat (this is a response to famine). So the level of caloric intake is not nearly as important as the body’s hormonal response to food choices.

I hope that provides enough information for you to begin to make some choices. If you have further questions, we will be glad to try to come up with answers. Meanwhile, there is a wealth of information in our Newbies forum. Have a look around and see if any of it helps.


@PaulL Thank you very much for your very thorough response.

(Christian Hirose Romeo Graham/廣瀬 グラハム クリスティン 路美男) #4

The most popular reason why is maybe insufficient protein, especially in a single meal. That’s one of the reasons why occasional OMADs are beneficial. You need an adequate amount of protein to bump up (not spike) insulin. Chronically flatlined insulin can wreak havoc on your body over time. One of the biggest mistakes on keto is to fear protein.

(Edith) #5

I think you may not be eating enough. You seem to be a healthy weight for your height, so maybe you don’t need to time restrict your eating window.? I would suggest having 3 meals a day and see if that helps with your energy levels. Not enough salt, believe it or not, can also cause a feeling of low energy. How’s your salt intake?


I would be surprised if my protein intake is lacking.

My diet every day consists of:

Water with electrolyte pill

10:30 Breakfast: 2 sausage patties, 3 large eggs, 1 whole grain tortilla, potatoes fried in coconut oil and beef fat.
3:00 Lunch: 1/3 lb Wagyu beef burger (high fat %), 3 slices of cheese on a whole grain bun. Fries air fried with coconut oil.
5:30 Late afternoon smoothie: Whey protein, milk kefir, psyllium husk, banana, blueberry, strawberry.
8:00 Dinner: this is the only thing that changes nightly. Could be steak, tacos, salmon.

I’m not easy on the salt. I don’t feel like that’s the problem. I could potentially take 2 electrolyte pills first thing in the morning instead of one to see if anything changes.

(May the blessing of bacon be always with you) #7

That’s a lot of carbohydrate. As you said, you are most likely not at a ketogenic level of carb intake. If you are lacking in energy, you need either to increase your carb intake, or else to lower it and replace the missing calories with fat.

This latter is not as difficult as it may seem, since fats generally contain 9 cals/g, whereas carbohydrate contains just under 4 cal/g. So, for example, it takes only 133 g of fat to yield 1200 calories, whereas it would take 300 g of carbohydrate. Fat is also a better source of energy than glucose (carbohydrate), because it “burns” cleaner, without the oxidative damage to cells. (Per molecule, they yield more or less the same amount of ATP, with about the same metabolic cost. Protein costs a lot more to metabolise, so its net ATP yield is much lower.)

Please note that our experience with increasing both carbohydrate and fat indicates that is a good way to put fat into storage. Please also note that our experience with cutting calories on a well-formulated ketogenic diet results in the body’s holding on to its fat store to the extent it can (this is a response to famine-level intake). So the most effective strategy is to cut carb intake to the bone and to eat enough fat to satisfy hunger.


This is one of the things I expected might be the issue. Too many carbs to go into ketosis, not enough carbs to give me enough glucose.
If I were to choose a new path to try, I think it would be easier for me to reduce carbs further. I don’t really like carby foods that much anyway. The most difficult carb source for me to get rid of would be my smoothie since it makes an easy vehicle for the kefir and fiber.
Another thing I would have to do is figure out another option for my breakfast sausage as these have 1g of sugar. This was one of the original reasons I added some carbs back to breakfast as an experiment and stuck with it.
My thought was at first I may have cut carbs and sugar enough that I was getting into ketosis, but then that 1g of sugar became enough to knock me out of it. I’ve been planning for a while to start making my own sausage. Now may be the time to start.

(Allie) #9

Yep. It’s known as low carb purgatory as it keeps you stuck between the two feeling crappy.


It makes perfect sense but I wonder why many people never have this problem on low-carb… I always wondered if my high fat intake all my life was the reason I felt great with 80g net carbs, never missed the carbs, in the contrary… Keto didn’t feel noticeably better.
Many people enjoys low-carb, some can’t function well on keto, just higher but still low-carb… So quite many people are different regarding this.

I wouldn’t think that tiny sugar isn’t a problem but who knows how sensitive you are…? I learned that almost anything is possible if it’s individuals and their individual body responding to their diet…
And you have so much carbs, try to reduce that first.
But if you find a less carby sausage, that’s a good thing, of course! Mine are very very low-carb but it must be the country, sausages are very easy to ffnd without added sugar. Other items are trickier but sausages are pretty okay.

(May the blessing of bacon be always with you) #11

Because we advise people to replace the energy from the missing carbohydrate by eating fat to satiety. This is standard advice from Dr. Phinney, Dr. Westman, Dr. Atkins, . . . .


But it doesn’t answer my question…
You say that carbs are fine in the “low carb purgatory” as long as there is enough fat? But surely some people have that problem… Just not everyone.

Starving surely causes problems on every woe…
(And people like me should never replace the missing carbs with fat anyway but it’s just me ;))

(May the blessing of bacon be always with you) #13

I’m saying exactly the reverse: fat is fine in the low-carb ketogenic diet, as long as the carb intake is sufficiently small. If carbs are too high for ketosis, then fat will be stored, even if there are not enough carbs to supply all the needed energy.


But it’s fine to be stored (some of it, I mean, just the unneeded amount), isn’t it? It will get used later then. My body surely stores fat all the time, my woe doesn’t matter. I have big, fatty meals, after all.

I talked about the lack of “low carb purgatory” for people who are thriving on low-carb (like 100g carbs) and there is no problems since day 1. They clearly use the big amount of fat even without ketosis. I did that. I used fat on high-carb too, of course, what else would a human body do on HCHF? (Okay, it depends on the amounts but my carbs didn’t give me nearly enough energy.) Fat was my main source of energy. So my body was used to it so when I cut out a lot of carbs and probably some fat too, I didn’t feel worse, in the contrary. But people going from HCLF to LCHF might have this “low carb purgatory”…? But maybe it’s more individual…? I don’t know.

I didn’t even notice a big difference when I went into ketosis, it felt very similar to low-carb, fat being my very seriously main energy source.

(Allie) #15

I think most people try to avoid this happening.


But we can’t avoid it with 1500+ kcal meals, can we? :smiley: (I personally need those.)

I don’t actually care if my body store fat for later or not. It doesn’t matter to me, I mean it’s inner workings I don’t need to care about. Important but not my conscious business.

I have most energy for a workout well-fasted and clearly my body gets out fat from the stores then… It need to get stored first. It would be super annoying to eat all the time. I am annoyed enough when I have 5 meals while doing IF!

(May the blessing of bacon be always with you) #17

Not when one is in “carb hell” and short of energy. That’s what we’re talking about, right?

If such people are metabolising their body fat, then they are in ketosis, which implies that they are pretty insulin-sensitive. It all depends on how much insulin the pancreas secretes in response to the carbs we eat. If you are really insulin-sensitive, 100 g of carbohydrate may be low enough to get into ketosis. On the other hand, some people are so insulin-resistant that even 20 g is too much for ketosis. It all depends. I’m sorry; I thought I’d explained that already.

The whole point is that when insulin rises to a level just under 25 μU/mL, it signals the body to store fat, rather than metabolise it. It’s not a progression; it’s more like an on/off switch. Any amount of dietary carbohydrate (whether that amount be a lot or a little) that raises insulin above that threshold cuts of fatty-acid metabolism and forces the body into metabolising glucose instead. Any amount of dietary carbohydrate (whether that amount be a lot or a little) that allows insulin to drop below that threshold allows fatty-acid metabolism and ketone production.

The total amount of calories is not nearly as important as what our body does in response to the type of food we give it. Give it a lot of carbohydrate, and it will burn some of that glucose and store the rest, along with any fat we’ve eaten. Give it very little carbohydrate, and the metabolism is free to burn fat and ketones and to rev up to match the amount of calories we give it. This has been discussed over and over and over and over in the newbie threads. You might find it helpful to re-read those explanations and refresh your memory.


I try to talk about the lack of low carb purgatory and its reasons, actually… Or whatever I can learn, how we burn fat on high-carb, when we store it on any diet…
If I need energy and eat a big carby, fatty meal, I get plenty of energy from that food… Getting fat out of stores can’t happen with high insulin, right? Using what is readily available should work. Whatever happens, I got my energy, on high-carb and low-carb alike, from very low-carb and carbier meals alike. The fat content was always high so I got plenty of my main fuel source. Whatever my body did, it worked well enough.

No, most low-carbers eating 80-100g carbs aren’t in ketosis. I weren’t but it still worked. I don’t know when I am in ketosis now but in the very beginning there were certain signs. My old 80g was very far from my ketosis carb limit and I never got fat adapted. But I had no low carb purgatory, I got my energy from fat as all my life.

You mean even what I just ate? Well I clearly didn’t need much carbs without ketosis to get my energy but I have no idea what happened there.
BUT LATER the insulin inevitably goes down and then we can get out fat.
It’s obvious that we humans use fat and burn body fat on high-carb too or else every people who eat much fat on high-carb would balloon up. The fat will get used up at some point (unless one eats too much or have some big relevant health problems).
It’s probably quite impossible to keep the insulin up all the time. we sleep sometimes, for example…
(Sometimes I wonder if there ever was an experiment with sugar eating every hour but with a low energy intake. There would be fat and protein too just not much. The victim probably would break down quickly…? Whatever, practically no one eats like that, we have breaks.)

But I need that fat too! But fine, it stores it and get it out soon when the insulin allows it. I need the energy, that’s why I ate all the fat and carbs in the first place.
Actually I don’t get how the body does things when I eat and immediately feel better. Only some quick sugar can get metabolized so easily! Or the hunger and weakness are just motivation to eat when the body still have plenty of reserves and it already took the fat out of the stores to use?

And I’ve read a lot of comments of yours (you wrote a lot of stuff I read many times already) and I don’t agree with the ones totally contrary to many people’s experiences, for example mine… It won’t change. But I ask a lot of questions and wonder about things, it’s too bad no one can answer them :frowning: But it’s a complex thing and scientists still know little… Oh well. I just hope I get info morsels here and there.

(Give my body a lot of carbs and it will use it as energy. Give it much fat and it will use it as energy. Give it both and it will use both as energy. And it won’t use my body fat to use as energy as my body is a jerk. In a nutshell.)

The topic went quite off. I was curious about the complete lack of low carb purgatory in the absence of keto. And yes, it wasn’t keto. People thrive on low-carb with various carb intake, way over their personal ketosis carb limit. I was curious about THAT.
But we need using the fat on HCHF too when our carb intake is pitiful compared to our needs… But at least the brain gets its glucose then… Okay, that’s a difference.

(Karen) #19

Even when I’m not keto I’m pretty low carb. And I never feel that energy burst. Bummer

(Christian Hirose Romeo Graham/廣瀬 グラハム クリスティン 路美男) #20

Then maybe I’d reduce or completely cut out salt intake for a while, to see if that helps. I believe that supplementing with electrolytes is more important than whether or not someone salts their food, on keto.