Carb overfeed vs. Keto overfeed


I’m curious to people’s experience with these. A carb overfeed, most commonly known as a “Cheat” day/meal. Consuming excess calories likely from a combination of both carbs & fat. In contrast, a “keto” surplus of calories, consuming an excess of calories while staying low carb. I realize Sam Feltham and Jason Wittrock did 21 day experiments with these, and I certainly applaud and appreciate them for doing so. However, I would believe them to be outliers, and woudl believe that most people would gain more weight than the two of them did on such a caloric surplus, low carb or not.

Either way, I’m curious of those experience with a keto friendly overfeed. What has your experience been, and how would you compare it to a traditional unrestricted overfeed? Were you much more satieted quicker with the low carb overfeed? How did you feel that day and days after? How was your weight and performance the following day(s)? Do you feel you create any metabolic advantage moving forward?

I personally can only speak to the traditional “cheat” day (or what I refer to as an “earned meal”). I would day the day of eating it, I don’t feel so great, just from being stuffed. However, the next day my workout is incredibly fueled, and I’m able to go forever. There is an initial jump up in weight the next 1-3 days, but I’m back in ketosis within 24 hours, with the help of fasting. I do like the flexibility to have carby favorites here and there and not being derailed. However, I’m intrigued on playing around with the low carb overfeed to see how my body responds to it. I’m interested in hearing others experience.


I don’t often do strenuous activity, I only know I should do them always in a very well-fasted state when I have most energy. And never in the morning as I have close to no energy then :slight_smile:

I rarely did massive overeating on keto (1000 kcal extra), I often did it to a smaller extent. It felt good. Satiation is the same and I noticed no difference as long as I didn’t stuff myself too much. Using my not satiating food items (added fat, cream) or as much carbs as I can afford on keto or maybe an extra late meal I can eat way more than my energy need with a perfect level of satiation. At least a bit more or much more for 1-2 days… 1000 kcal extra every day only happened one month on low-carb, before keto. (Without any weight gain due to some not very common but not too rare genetics as far as I know.)

So on keto, it’s normal.
I never overate on carnivore.
And on HCHF… It’s bad. But high-carb is bad without overeating too (if I find some way to do that. carbs almost always caused overeating until very recently but not on OMAD, for example). I become enervated (as if I had much energy to begin with!), usually unwell to some extent, it varies, I become too full more often if I use carbs… These aren’t good. And my body throws its temper tantrums because I dared to stray away from its favorite woe… I probably don’t feel much desire to move either… Bad idea.
Next day it may be fine unless if I was too crazy with my carbs (I am still a bit unwell and enervated then) but never better than on keto. Or very occasionally. Sometimes very much carbs cause no problem at all, I don’t know why. But usually they are a problem.
But again, my exercise never very strenuous yet and I can cycle using my own pace for some hours on any woe without problems…

I always have high-calorie days now and then. It’s automatic. So it’s probably something my body needs when I eat less than my energy need. I feel fine and satiated but suddenly more calories come. My body guides me well. It tells me what it wants and it’s never carbs. It tolerates some slightly carbier days now and then but that’s it. When I did keto for months, I never felt the need for carbs (I missed my big amount of vegetables but it wasn’t a need). But I never had a high activity either.

(Michael - When reality fails to meet expectations, the problem is not reality.) #3

Eventually this question will resolve itself. You will someday laugh about it.

(Bacon by any other name would taste just as great.) #4

As a former pre-diabetic, if not actual diabetic, I try not to consume excess carbohydrate, though as a sugar/carb addict, I often find it difficult. But I notice that even if I don’t go far enough overboard with carbohydrate intake to inhibit ketogenesis, I end up with all my aches and pains back: creaky joints, arthritis, and the generalized crappy feeling that I used to associate with getting old. I don’t feel that way if I keep my carb intake low enough.

On the other hand, when I fail to listen to my satiety hormones and overeat fat and protein, what happens is that I sweat a lot, especially at night. Since I dislike clammy sheets, I try to satisfy my addictive tendencies in other ways, but I do overeat often enough that I know what I can expect.

It’s worth noting that the weight Sam Feltham gained on his keto overfeeding experiment was muscle, not fat. And Gary Taubes mentions in Good Calories, Bad Calories an ad libitum keto feeding experiment, in which one of the subjects ate a 3000-calorie diet and still lost just as much fat as the other guys in the study. He also quotes a case study published by the Dupont corporate physician in the 1950’s and -60’s, who had great success getting a particular executive to lose a great deal of excess fat on a low-carb diet, but found that if the executive ate even one extra apple, he would gain weight. There’s a lot of individual variation here, so everyone’s kilometrage is guaranteed to vary, but my suspicion is that insulin resistance and chronic systemic inflammation have a lot to do with the results.


Agreed, Whitrock is a genetic freak.

I’ve flip flopped many times on the intentional overfeed / caloric burst to see what happens in the gym, never changes. When it’s a LCHF burst I definitely did better, but can’t even remotely compare to when I’d do it with carbs. When I hit the gym with the glycogen tanks on full I feel like a beast and my lifts show it all day long! The reps just keep on coming and clearly the skin tearing pumps can’t be beat. When I read of people saying it’s the same for them with vs without I just gotta call BS. Or at least question what “going to the gym” is for them.

I feel at this point I’m about as metabolically flexible as you get. I typically run my diet at this point like a phased workout. Pretty much mini bulks/cuts. My protein is constant throughout but my carbs/fat throttle depending on where I’m at in my plan. I can go from weeks of 300g carbs a day and 100g fat down to 200 or 50g carbs a day without a hiccup. No keto flu, no energy drain, no nothing. The only place it’s noticeable is my workouts are a little harder on the back end but I just keep on chugging. I don’t think there’s much of a satiety difference for me on either end as long as my protein stays up.


What happens in regards to fat overfeed is what happened in the following research paper.


Keogh at al53 recently demonstrated that 8 weeks of a very-low-carbohydrate, high-saturated-fat weight-loss diet reduced plasma PAI-1 levels in severely obese individuals with a body mass index of 33.64.1. However, the beneficial effect of this diet seems rather to be a result of weight loss, because plasma PAI-1 levels are also reduced by an isocaloric high-carbohydrate, low-saturated-fat diet in the obese subjects. On the other hand, the effects of kDa on blood fibrinolysis have not been examined in nonobese individuals as far as we know. Our present findings suggest that the nature of kDa with respect to the prevention of thrombosis is a double-edged sword. The morning increase in PAI-1 plays an established role in the mechanisms underlying transient morning resistance to thrombolysis using tissue-type PA, as the activity of PAI-1 is 2- to 4-fold higher in the morning than in the evening.5 Therefore, the kDa-induced circadian augmentation of PAI-1 expression in a phase advanced manner not only contributes to an increased risk of myocardial infarction but also alters the efficiency of thrombolytic therapy when applied in the morning.

The last part I crossed out because it’s due to overfeeding and she’s contradicting herself.


I’ll report my experience with both an overfeed with plenty of carbs, fats, and protein vs. a lower carb overfeed, as well as a documented study.

My carb overfeed:

Ate plenty of carbs, fats, and proteins all at once. Big surpluss of calories. Did two workouts that day to minimize damage. Ended the day with stomach bloat/distress and a bit of a food coma. I will note that I use to be able to put away a lot more food before going keto. Part of that likely being just being use to reduced overall food volume and reduced calories on this cut, and partly being fat adapted.

My low carb overfeed:

A ton of fat was consumed. Carbs did go over 50g, but the ratio of carbs to fat remained somewhat in keto-ish proportions (though I didn’t track). Stomach bloat/distress and food coma still occurred. I’d guess calorie-wise, I consumed a similar amount to the carb overfeed.

Similarities were that I ate far too much on both days, to the pint of discomfort. Likely similar calorie totals. Both ways I exercised very heavily the day of the overfeed. Therefore, there was the damage the following few days, but my weight was lower by the end of the week. Lower than the day of the cheat, due to returning to reduced calories and plenty of exercise.

Differences were -

I definitely had much more energy the day after the CARB overfeed. I worked out the next day. Once I got a sweat going and got over that brain fog from the overfeed, I felt like I could go forever. Ended up biking a long distance then even running after. I easily fasted the entire next day, then continued fasting for a total of 72 hours. Day 2 and day 3 evenings were not so easy, as hunger always sets in for me at these points.

On the low carb overfeed, my energy was normal the next day. Not more, not less. My appetite was basically the same. The next day, I ate roughly 2/3rd of what I would normally eat, then returned to normal the proceeding days.

It was after experimenting with this that I saw this study:

The study supports my experience in the sense that the carb overfed participants saw an increase in leptin by 28% (less hunger), and an increase of 7% in BMR. The fat overfed participants did not see changes in these areas.

And yes, a good approach would be simply not to overfeed yourself to the point of discomfort :smile: Either way, interesting information and experiences.