Why would my metabolism slow down if I’m getting cals from fat stores?


That’s a nice flat curve.

I run my post pradnial glucose curves out to 2 hours. It’s in case, in the future, we get access to at home blood insulin testing. I think the standard Kraft test data on blood insulin is a test at 2 hours after a meal.So I just want the historical data available at the 2 hour mark.

(Eric - The patient needs to be patient!) #82


This week, probably Friday, I’ll do this again after lunch. If my schedule allows I’ll go 2 hours. I’ll just report back here the results.

(Ilana Rose) #83

This study only examined the effects of three different diets on the weight maintenance phase after a 12 week weight loss plus four week weight stabilization period where all test participants were kept on the exact same diet (45% carbohydrate).

What they were comparing was metabolic rate from before the weight loss phase to after a four week period of maintenance in one of three diet arms. The low carbohydrate diet returned the metabolic rate furthest back to the pre diet levels.

Also, the three maintenance diet arms were each only four weeks long and so definitely not long enough to achieve full fat adaptation. That the low carbohydrate diet arm participants were under some metabolic stresses during that period is suggested by their higher cortisol excretion and inflammation as measured by CRP.

It’s also important to remember that some degree of metabolic rate lowering is virtually inevitable and not bad when a person significantly lowers their body mass. Slim people on average have far lower metabolic rates the obese people because their is less mass that needs to be supported with energy.

What we are concerned about is not any reducing of metabolic rate with fat loss but rather one that is so steep that maintaining that weight loss becomes a constant battle with hunger and further restriction.

What this experiment beautifully demonstrates is that people in maintenance on the low carbohydrate diet had a TEE on average 300 calories higher than those on the low fat diet. And this was found in spite of the fairly short term periods of the diet arms.

(Ilana Rose) #84

There are a lot of issues with this study. First of all any comparison of the effects of the interventions between men and women is utterly ridiculous for a few reasons. The first one is that the men in this study were on the two diets for 50 days each while the women only 30 days. The second is that the level of caloric restriction was considerably higher for the women. So the findings of large differences in effects are hardly surprising especially when the women would never have even gotten past fat adaptation.

As I said before we can’t expect absolute REE not to drop concurrently with body mass. A 5’5 105 pound woman does not require the same calories, on average, to maintain her weight as a 5’5 250 pound woman. But the fact that the smaller woman has a much lower REE does not mean the she has greater difficulty maintaining her weight.

What matters is which diet results has the least reduction of REE with weight loss.


Interesting ideas, @Paul. But are 1, 2, & 3 are necessarily separate states from 4 & 5? Many people are “eating to satiety” (#4) and this lowers their caloric intake (#3)–that’s why they’re losing weight and aren’t hungry, but their metabolic rate is also dropping. Or they’re “eating to satiety” and not losing or gaining (#1), because that generalized guideline isn’t lowering their intake enough to where they start tapping into stored energy. “Eating to satiety” is a nice representative mental state, but it doesn’t necessarily tell you anything about someone’s energy intake.

So if you keep your energy intake high enough to prevent weight loss, there’s nothing inherent about keto that would cause it to drop. Which is good confirmation. I think we have lots of anecdotal evidence from people who have met goals and stayed on keto for years afterwards maintaining those goals without any noticeable additional drop from what they experienced while losing weight.

(Michael - Don't expect miracles and you won't be disappointed.) #86

@ZuleikaD My experience may be relevant in this context. At 71, 6’0", 175-180 lbs, retired and relatively sedentary male, I started keto with the intention primarily of adopting a healthy lifestyle to get the most out my remaining years. I also wanted to get down to 160 lbs which feels much better than 180 lbs. Not knowing much about anything I adopted a very strict keto diet regimen, weighing and measuring food portions to predetermined fat:protein ratios as best as I could determine from multiple online sources. Also not knowing anything I presumed my daily energy need was probably around 1800-2000 calories. So to lose the weight I started out eating 1500 calories per day.

Almost immediately I started losing about 2 - 2 1/2 pounds per week. After 2 1/2 months I had lost about 25 pounds and I decided to stop. Doing nothing else with my daily diet, every couple of weeks I upped my daily calories by 200. Doing this slowed the weight loss but did not stop it. I continued to lose weight, although more and more slowly, until finally I got to 2500 calories per day. At that point (May/June 2017) the weight loss stopped and I weighed 150 lbs.

A year later (June 2018), with no changes to overall ratios and diet intake, still weighing 150 lbs, I landed a full-time job at my local Walmart. This requires lots of standing (no sitting on shift) and walking. I started losing weight again! I went down to 145 lbs before I got my daily calories up to 2800 where the loss stopped.

I eventually reduced my daily calories to 2700. If I eat my 2700 daily(+/-100) I maintain my weight, less for more than a few days (3-4?) I lose, higher for more than a few days (again 3-4?) I gain.

Right now:

  • Weight: 141 lbs
  • BMI: 19.1
  • Lean mass: 124 lbs
  • Fat mass: 17 lbs
  • Body fat: 12%

Basically during my 2 1/2 years of eating keto, my diet regimen has not changed overall other than my exact fat:protein ratios. My current ratio is based on protein intake as suggested by Bikman: 1.4 g/kg of total body weight. This is the higher side of Bikman’s recommendations because as a 73-going-on-74 years young male I think I need a bit more protein. This currently works out to 90 grams of protein per day. My fat intake is based on protein times my ratio to total 2700 calories.

(Karim Wassef) #87

It’s really simple. Metabolism drops when total energy available drops.

Total energy available = energy from your body (glycogen and fat) + energy from food.

If you reduce energy from food but access to your fat reserves is enough to provide the difference, then your metabolism does not drop.

If you reduce energy from food but access to your fat reserves cannot make up the difference, then metabolism drops.

The access to your fat reserves is determined by insulin (low insulin = more access), fat mass (more fat = more access), and the transport rate via fat adaptation (more adapted = more access).

(hottie turned hag) #88

@Karim_Wassef slays again with a Keto For Dummies in a nutshell post :smiling_face_with_three_hearts:


I am no scientific genius–quite the opposite–but I read the studies I referenced to say that metabolism dropped when intake dropped. Even the obese people (who would have plenty of fat stores to add to total intake) in these studies experienced metabolism drops on keto diets.


The suppression of appetite has been shown directly correlates to BohB levels and circulating FFA (NEFA) in ketosis.

Our findings of elevated NEFA after 8 weeks on a low-carbohydrate VLED with return to baseline values after carbohydrate reintroduction are not surprising, as carbohydrate restriction stimulates adipocyte lipolysis and ketogenesis.

It has been hypothesized that fatty acids may provide a signal to the hypothalamus of nutrient abundance,8 and this may contribute to the appetite-reducing effects of ketogenic low-carbohydrate diets. https://www.nature.com/articles/ejcn201390

…the long-chain fatty acid oleic acid [common in animal fat, therefore lipolysis -ed] provides a signal of “nutrient abundance” to discrete areas within the CNS. This signal in turn activates a chain of neuronal events apparently designed to promote a switch in fuel sources from carbohydrates to lipids and to limit the further entry of exogenous and endogenous nutrients in the circulation. https://www.sciencedirect.com/science/article/abs/pii/0026049578902615

I take these 2 studies together to mean that endogenous release of FFA has the same effect as adding fat into the system. Total energy is maintained.

(Michael - Don't expect miracles and you won't be disappointed.) #91

That certainly has not been my experience. Changing to primarily fat calories from carb calories has increased my metabolism, even when I reduce calorie intake.

(Karim Wassef) #92

This is why eating fat maintains energy levels and RMR. If you’re slim and want to maintain a high metabolic rate, you need to eat more fat.

But a high metabolic rate may not be the best for longevity due to higher oxidative stress - even though fat oxidation is relatively benign compared to glucose oxidation… and ketones are protective. @Ilana_Rose

I personally enjoy the energy boost… :smiley:

(Karim Wassef) #93

That’s because they cut back to a level lower than what their body can replenish with their own fat. This is why calorie restriction fails, especially in extremes.

There’s four zones of cutting back…

Reduce dietary intake a bit (and be low carb) = safe zone keto with no RMR impact.

Reduce intake more (and low carb) = aggressive zone keto with some RMR impact but mild.

Reduce dietary intake a lot (but not fasting) = danger zone, RMR will drop

Fasting = safe zone, RMR will drop temporarily but new processes kick in to be protective. RMR recovers on refeed

(Eric - The patient needs to be patient!) #94

I hope this is right because that is my approach.


I didn’t see that in those studies.

(Give me bacon, or give me death.) #96

When I read the collective wisdom of these threads, I am simply amazed that our ancestors managed to survive. How did they do it, with no supplements, without equipment to measure their BMR, no blood meters, without even the least knowledge of what a calorie is? Obviously, we would all just drop dead if we relied on our bodies to handle things without supervision . . . .:rofl::rofl::rofl:

(Karim Wassef) #97

I don’t think they were all super fit either… especially the wealthy

Beer and bread have broken many cultures



From a review of multiple studies, Volek comments on his own study (linked above) thus:

Study 8:
…There were greater reductions in leptin after the VLCKD (50%) than the low-fat diet (17%). The ratio of leptin/total fat mass also decreased more after the VLCKD (45%) than the low-fat diet (21%).
REE (kilojoules per day) was significantly decreased after the VLCKD (4.2%) and low-fat diet (9.0%). Expressed relative to body mass (kilojoules per kilogram), REE was not significantly affected by the VLCKD (2.3%) or low-fat diet ( -5.7%).
This study has shown that, compared with a low-fat diet, a VLCKD resulted in 2-fold greater losses in body mass and whole body fat mass and 3-fold greater losses in trunk fat. There were also differences in insulin and leptin responses that were related to the changes in body composition. https://onlinelibrary.wiley.com/doi/full/10.1038/oby.2004.276

The REE section per kg has been labeled “not significant” but clearly there is a difference between the two approaches, one going up the other going down. Also, still no access to raw data that would relate fat mass to REE change. I suspect there will be more data on longer term studies in the future, such as being done by Virta Health.

(Ilana Rose) #99

I’m so glad that you posted this. I didn’t really understand it when I read it myself and I thought maybe you’d know the answer to my questions. If leptin is the satiety hormone then why is a reduction in leptin in a good thing?

Do you know what the significance of the ratio of leptin/total fat mass is?

Oh WOW. This I had not seen. so the relative REE actually went up on the low carbohydrate diet. Fascinating!


Kind of like insulin, higher isn’t better is you have leptin resistance. Insulin and leptin interfere with each other in the brain also, I think. @PaulL ??

Adipose tissue produces leptin to try and tell the brain to 'slow down on the eating, already! ’ If the signal isn’t getting through, levels go up.