T Nation

leptin questions (long)

A preface to my questions

once Re-feeds and cheat meals where done on some vague scientific data about re-stimulating metabolism, re-stimulating thyroid functions, phsychological(sp??) stuff etc. their content was anything from whole cows to poor innocent bystanders. no specifics.

now it’s done on the (disputed) notion that through stimulating leptin production, we can jump start the fat loss which stopped due to reduction in serum leptin levels

Although john berardi is opposed to refeeds, from his article on leptin I gathered that leptin production is correlated directly to fat gain due to carbohydrate metabolism to triglycerides and storage of the last ones. since none of that happens (hopefully) when we diet we need to stimulate it ourselves.
So how much fat do I need to gain before I can go back to dropping fat? I dont think anybody can answer that right now.

Question A:
I didnt see anything in JB’s article that says refeeds are only for lean people or that serum leptin levels are related to the number or size of adipose cells. so why do all the recommendations for refeeds say that they should start at a low BF? if someone hadnt experienced a fat gain due to carbohydrate metabolism to tryglicerides and storage of those tris wouldnt he be subject to the same drop at serum leptin levels, no matter how fat he is?

Question B - Refeeds and Hot-roxx:
On the “we made ephedra obselete” it is said and I quote “Additionally, both increased cAMP and high T3 levels decrease lipoprotein lipase activity, which is an enzyme responsible for lipogenesis. So in addition to stimulating lipolysis, cAMP and T3, as a team, put the kibosh on lipogenesis as well.” so we shouldnt take hot-roxx with our refeeds otherwise we will not gain fat enough for leptin to be produced?

Question C:
Is the metabolism of glucose to tryglicerides BY ITSELF a leptin stimulator or do they have to be actualy stored? if the answer is yes then it answers question B right?
why do I ask that?
Bill roberts said in the hot-roxx forum, “refeeds and hot-roxx thread” this: “Decreasing tendency towards lipogenesis in the refeed would be a good thing” so he is implying that this might be true. otherwise he contradicts what JB is saying.

thanks for anyone who could clarify


  1. Leptin levels are related to two things. One, your current level of body fat, and two, your caloric intake. If you are on a calorie restricted diet, regardless of your level of body fat, your leptin levels will drop. I recommend periodic overfeeding for all dieters, including fatter ones; however, a more moderate approach seems to work better for them, most likely due to the fact that they have higher baseline leptin levels.

  2. Taking Hot-rox is fine. Leptin levels are stimulated by consuming a surplus of calories and carbohydrates. Even studies in which subject only consumed maintenance calories after a fast experienced a rise in leptin back to baseline. I don’t think there is substantial fat gain occuring when consuming maintenance calories. There isn’t any measuring device sensitive enough to measure fat gain from one day to the next anyway, especially when overfeeding and the massive amounts of intramuscular and subcutaneous water retention that occur. We do know from many studies that increasing caloric and carbohydrate intake stimulates a rise back to baseline leptin levels. That’s all one really needs to be concerned with.

  3. An increase in caloric and carb intake equals an increase in leptin; we know that. So, if you increase you carbs and calories, you get an increase in leptin.

A couple more things; one, I think you are making things more complicated by worrying about minutia such as this. Whether you take Hot-rox on a single day or not isn’t going to make much of a difference in terms of measurable fat gain, IMO. The product has a cumulative effect over time which makes it worthwhile.

Also, recognize that Bill’s recommendations are for glycogen replenishment ONLY, and are not based on leptin research. They are very accurate numbers to restore muscle glycogen stores when restricting carbohydrates throughout the week. So, of course minimizing fat gain is desirable for that purpose (not that I think it really matters when overfeeding anyway, just up the cals and carbs).

This is why I have been trying to get individuals to seperate the terms “refeed” and “overfeed.” They are not the same thing. However, everyone wants to use the terms interchangably (mostly using the term refeed wrong), and it just confuses people. The purpose of a refeed is to restore muscle glycogen when on a low carbohydrate diet. An overfeed is to restore leptin concentrations and prevent plateaus in fat loss; it has nothing to do with whether you are on a low carb diet or not. It really doesn’t have anything to do with restoring muscle glycogen (even though that obviously will happen, but it is not the reason for implementing overfeeds into your dietary regimen).

Lastly, we don’t know if leptin is the sole reason that overfeeds work. It most likely is not. However, it certainly plays a role and is the easiest way to explain what is happening. There are most likely plenty of agonistic and antagonistic reactions taking place along with changes in serum leptin, and possibly even some reactions that take place completely independent of leptin to explain the positive results that dieters are obtaining with overfeeds.


Also, John is not “opposed” to overfeeds. He stated in the article that apart from leptin, he still believes there are plenty of reasons to overfeed (more intense workouts, better adherance to the strict portion of the diet, greater maintenance of LBM, psychological vent, etc). He is currently using my CD/EDT approach with a number of his paying clients. I don’t think that he would be using an approach with people who pay him money to get results if he didn’t believe in it.

At this point, John does not believe it is leptin that is responsible for the results. That is his stance until he sees some research supporting that to be the case. Unfortunately, there are no studies measuring leptin levels as a result of overfeeding with a moderately calorie restricted diet, only fasting (which doesn’t give us much insight, IMO). Also, there is no data measuring the speed of decline of leptin levels once moderate dieting resumes; until then (if indeed it does), John does not want to say that it’s leptin that is responsible.

What I have done is read just about everything that is out there on leptin, and from that, I’ve made some recommendations for dieters. They work; just ask 90% of the people who have tried it. I noticed a long time ago that trying to stay strict on my diet did not work; I experienced considerably less results everytime I tried to throw out that “free day.” I’m not the only one, tons of people can probably relate to that last statement. We are just trying to figure out the means as to how this works, because indeed it does.


Hey joel

thanks for your time.
Im not confused about refeeds and overfeeds, I did read your MM article when it was published(before I found this site) and I’m not trying to make you and berardi fight naked in ketchup.

I did however understand from JB’s article that described the exact mechanism that effect leptin production that some fat gain is necessery for leptin levels to rise. thats why I asked all those Qs.

thanks for clarifying.

BTW, although controlled carb overfeeds are fine on paper cheating without fat is not cheating…


Excellent, Excellent, Excellent

I might suggest you take a look at some other threads Joel and I have devoted to this topic (as well as others)…As Joel pointed out, key differences need to be noted in regards to:
CHO Load

De Novo Lipogenesis


Thanks vain but I allready did, believe me.

my questions are not clear?

Oh wow vain sorry!

I just read your “de novo” thread

that was what I missed here.
so the question is do you think de novo has to occur for leptin to bumped up?

if so then I dont need to be keto at all, on the contrary I’ll reach the novo with fewer carbs if Im not keto right? and to hell with depletion workout It will just make me need more CHO (leave the sychological benefits of overfeeds aside)


You guys think way too much. I hope your physiques match your reading skills or will.

To greekdawg:

why do we need physiques for? we are eveolving into Homo Cyberneticus - just fingers, eyes and brain.

just kidding

I guess it’s a personality thing, for me first came the knowledge then came the physique, allways been that way for me

also, I (sometimes) view cheating and overfeeding as such a bad thing full of guilt and stuuf, that I have to understand it correctly before I do it (and I will do it)


Another question to joel that popped in my mind

If you are saying that what matters is the number of carbs’ not if you get fat a little or not, then why should they be high GI, all of them?



it has to do with insulin. Carbs alone do not seem to be what raises leptin levels but rather the insulin response they trigger.

Joel will elaborate more I am sure.


It’s most likely the insulin spike. The study that I base the high GI recommendations from took a look at a number of diets containing either high or low GI carbs. They founded that while the lower GI diets didn’t have a substantial effect on leptin, the high GI diets did. However, they also analyzed insulin response (total insulin in 24 hours) and found no difference. So, it seems to be that the issue is insulin spikes, not total insulin…then again, it may not even have to do w/ insulin, it may be though another property that high GI carbs possess. Either way, the study shows high GI carbs to be more effective at raising serum leptin levels, and that is the important part.


A couple of comments:

One: I don’t have much in the way of “scientific” research to back me up, but I can tell everyone from here to Hyaleigha that refeeds work. Period. And they work with Hot-Rox - better, in fact, than they worked with a combination of MD-6 and T2-Pro at maximal doses. Take a look at my HR contest report for more details.

Two: For Joel: You might want to start talking about “glycogen refeeds” and “leptin overfeeds”, since the majority of people seem to be conflating the two terms. (Just a little advice from a linguistics POV. :wink: )

Whether leptin is influenced more by lipogenesis, insulin, or simply having a “fed” cell, eating higher GI carbs, and thus stimulating a lot of insulin, will accomplish these goals quicker.