View Full Version : IF, Thyroid, and Body Temperature

Steve Liberati
05-07-2007, 12:11 PM
Body temp will decrease on IF. That can be good if you live in Chico in the summer and it's 45*C. Not so nice when its cold.

Robb made a good point the other day that got me thinking about IF's affects on thyroid output and body temp. Per his quote, "Body temp will decrease on IF." This makes sense, since body temperature (heat output) Is a direct measure of the amount of fuel (food and oxygen) being burned by the cells. Since no food is being ingested into your body, your metabolic rate (and therefore thyroid hormones should naturally dip. In other words, once you stop throwing wood in the fire, it will slowly but start to fade away. Of course, this is the logic behind eating six small meals every two hours to keep the fire (metabolism/thyroid output) constantly blazing.

We know a healthy thyroid function is not only crucial for improving one’s body composition, but just as important for graceful and vital aging. So if IF decreases body temperature below the normal metabolic rate (A normal metabolic rate will produce a waking temp of between 97.8 and 98.2 deg F), is IF as beneficial as we think it is?

While the verdict is still out, I think a simply test we can all do on our own can perhaps give us a better idea at how effective IF really is and its affect on thyroid function and metabolism. Perhaps knowing more about the changes in our metabolism we can have a concrete way of how IF affects the digestive and endocrine systems.

A few years back, my younger sister was diagnosed with hypothyroidism. Upon hearing this, I immediately grabbed interest and researched the subject as much as possible. At the time, I was trying to help her lose weight naturally with good ol' hard work and was afraid she would use the slow thyroid problem as a excuse to throw in the towel and turn over to the professionals. To make a long story short (after taking one test after another so every specialist known to her family physician could get their little hands in on the action) she gave up and went back to the natural route under my guidance. Anyway, this whole fiasco with the doctors lead me to spending much time learning about the thyroid and how it affects the body. Its actually quite overwhelming how complex the thyroid is and its relation with the rest of the body.

But...and I promise this post will end soon....but there was this simple test she did every morning (as soon as she woke up before getting out of bed) that was used to measure her thyroid function. Basically what you do is check your basal body temp immediately upon awakening and follow these simply steps:

1. Keep a thermometer by your bedside so you can take your temp before getting out of bed in the morning. (It is important to move as little as possible while taking your temp.)
2. Shake down the thermometer to read less than 92.0 deg (unless you have a digital, which I recommend.)
3. Upon awakening in the morning, take your auxiliary (armpit) temp for at least ten minutes.
4. Record your temp.

Repeat these steps for four days. (Menstruating women should record their temp on the second, third, fourth, and fifth days of their periods.) Calculate your average temp for four days. A normal metabolic rate will produce a waking temp of between 97.8 and 98.2 deg F. Temp below 97.8 may indicate, at the very least, subclinical hypothyroidism. Temperatures higher than 98.6 may reflect hyperthyroidism.

Here's more:
We know thyroid hormone increases the utilization of carbs and fat from food, and the rate of protein synthesis. It stimulates the appetite and the movement of food through the digestive tract. In the presence of thyroid hormone, muscle catabolism increases, which increases the resting metabolic rate (muscle burns more energy than fat). Thyroid hormone also increases the sensitivity of skeletal muscle to impulses from the spinal cord. (An excess of thyroid hormone is known to cause tremors, and a deficiency results in sluggish muscle response.) Thyroid hormone increases the uptake of oxygen into the cells, which speeds aerobic respiration. Finally, thyroid hormone actually increases the number of mitochondria within the cells.

As mentioned, the endocrine glands are in constant communication, not only with each other, but also with the nervous and immune systems. In conjunction with the pituitary gland, thyroid hormones influence almost every function in the body, as metabolism establishes the official temp at which systems operate. Because the thyroid gland's work involves interaction with many body systems, it is particularly sensitive to influences that can disrupt its proper functioning.

So what does all this have to do with IF?

Well, IF might be causing such a high stress on our body that PERHAPS and I used this loosely that fasting too much might reverse all the positive benefits of IF.

We know chronic stress affects the thyroid and endocrine function in a number of ways. The pituitary gland, the bodies "master gland," stimulates and controls the function of the adrenal cortex by secreting adrenocorticotropic (ACTH). If required to maintain a constant level of the major stress hormone cortisol in response to stress, the pituitary gland may over work. Too much production of ACTH may divert the pituitary from manufacturing other tropic hormones such as TSH, FSH, and LH. Cortisol production requires tyrosine, the same amino acid needed for the synthesis of T4. Excess cortisol production can deplete tyrosine levels, making it unavailable to the thyroid gland to make thyroid hormones. Stress depletes other important nutrients for T4 production, namely chromium and zinc. Excessive cortisol production from chronic stress also inhibits the conversion of T4 to T3 and the secretion of TSH. So the takeaway message (at least for me) is too much stress is obviously NOT a good thing over time.

So to FINALLY wrap this one up (sorry!) perhaps ALL our IF participants (and I know we have our fair share on this board alone)...keep a daily log of your resting temperature (remember first thing in the morning) and observe the patterns of higher temps on feed days vs. lower temps on fast days or steady temps throughout. Who knows what will happen.....perhaps this could be another tool from our BLACK (tool) BOX (inputs vs outputs concept) to use in our arsenal. Along with observing changes in body comp, performance, energy levels, sleeping, etc...we can track our body temp (very economical by the way!) and gauge other parameters such as metabolism and thyroid output.

Hopefully IF will become more popular, and in addition, the various influencers of thyroid metabolism such as stress and nutrient abnormalities will begin to become more recognized in the coming decade.

So what other IF's are up for checking their body temp every morning for the next few days? Curious to see the findings.

Garrett Smith
05-07-2007, 01:41 PM
I'll do it, I'm on week three of IF.

Again, since the iodine issue came up today on the board, in a "normally" eating person with a low body temp, I'll always look to iodine first before thyroid hormone. All this Wilson's thyroid syndrome stuff, IMO, is simply iodine deficiency happening on a massive scale--there is enough thyroid hormone(s) to show up as "normal" on tests, yet not enough iodine to have the proper conversion of T4 to T3 or for the iodine-dependent tissues to function properly--hence a hypothyroid presentation with completely normal labs. I mean, I've seen several instances of patients being treated for goiter with thyroid hormone!!! It's a basic nutritional deficiency (iodine)!!!

Combine an iodine deficiency with heavy metal toxicity, and there are so many pathways of the body that won't function right it's unbelievable! That's why those two tests are always near the top of the list of tests for ANY patient I see.

Before IF, I was one of the few people I know with the "normal" body temp of 98.3-98.4 degrees F, that was after the iodine supplementation I mentioned in the other thread.

Steve, let me know if you want to start this as a group or if I should just go on my own...

Steve Liberati
05-07-2007, 02:05 PM
Good point on the iodine, although a regular serving of sea salt should be enough to do the trick for most people. Of course sea vegetables (nori, hijiki, wakame, kombu, and kelp) are the better of the two options. Iodized salt is another source for iodine, but contains too much aluminum. The one supplement that I would highly recommend for this purpose (proper functioning of the thyroid gland) besides trace elements iodine and selenium, and the amino acid Tyrosine...is BLADDERWRACK.

Bladderwrack, or fucus, consists of the marine plant fucus vesiculosus. Marine algae have been used in Europe and Asia as medicinal agents for thousands of years. Bladderwrack is a rich source of iodine and is traditionally used for weight loss and hypothyroidism. Bladderwrack is thought to stimulate the thyroid gland, thus increasing basal metabolism. Bladderwrack also contains potassium, magnesium, calcium, iron, zinc, and other minerals.

At any rate, go forth and track your temp on your own Garrett. Curious to see if any major consistency/inconsisties show up as a result of IF'ing. Based on my experience so far with IF, I'd suspect the law of diminishing returns cannot be overcome with IF either. Fasted EOD for months with greater than better results...recently (as in last 3 weeks(tried fasting everyday up until 5pm) and noticed a drop across the board in most all my fitness parameters. Feel like I got slapped in the head for my my "more is better" attitude.

Steve Shafley
05-07-2007, 02:24 PM
The thyroid is a tricky gland, and the hormonal replacement of thyroid hormone is also tricky.

Bits and Pieces:

From discussions about panhypopituitarism, there are a significant number of folks who prefer the Armour thyroid preparation instead of levothyroxine, and feel better on it. Endocrinologists seem divided on which they prefer.

There are a few folks I know who regularly use anabolic steroids, and they've told me that taking T-3 is the difference between an mediocre cycle and a very productive cycle, given the other variables remain the same. They all, after regularly supplementing their cycles with 150-200 mcg of T-3 on a daily basis, for over 8 weeks, have a fully functional thyroid (after the HPTA rebound occurred)

I do not think you can look at body temperature upon rising, in a healthy individual, and comment upon there thyroid output without a hormonal make-up before hand. A few years back I had some thyroid test done (my doctor wanted to check the levels so he could prescribe me some drugs if I was deficient...didn't matter what drugs, but he was hoping for statins, diuretics, and maybe thyroid too) and I followed a similar procedure to chart my temp...borderline low, but my thyroid output was fine.

I do not think that IF is going to affect the hormonal axes more than CR might, CR is, by far, a much more dramatic intervention in the energy balance of an organism.

Steve Liberati
05-07-2007, 03:07 PM
I frequented several bb'er boards in the past (for the nutrition discussions) and remember the guys always raving about using T-3 and clen for taking off that last stubborn layer of fat around the waist. Seemed to work well for them, although overloading your system with synethic chemicals can't be a good thing over the long haul.

About the test, I agree its not a no questions asked way to determine thyroid output by no means. For this, blood work would be more useful. Rather, it is simply a tool (the most logical assessment) for measuring thyroid function--that is, determining the ability of thyroxin to enter the cells and influence metabolism.

In fact The late Broda Barnes, MD., a pioneer in the diagnosis and treatment of thyroid disorders, developed this test and successfully diagnosed and treated many patients based on its results.

Again, not proposing any groundbreaking theory or anything here....just interested to see if there is any relation b/t IF and body temp, as we know a change body temp is telling us something else worth noting is going on.

Garrett Smith
05-07-2007, 03:26 PM
I must respectfully disagree with your opinions on sufficient sources of iodine from foods in today's SAD diet. I don't even believe that major iodine deficiencies can be made up with sea vegetables eaten in (eventually sickening to the stomach) large amounts. I base this on the feedback of my patients, both those who have gone from eating large amounts of seaweed to iodine and those who have gone from taking the Iodoral iodine to a solid dose of seaweed in supplemental form. Everyone noticed improved "function" on the iodine supplement and not so much on the sea vegetables.

Men in general underestimate the needs of iodine, as men tend to have much fewer issues with deficiency. I believe this is mainly due to the high requirements of iodine in females, both in their reproductive organs and due to childbirth (low iodine in newborns = cretinism, no mother's physiology will allow that to happen without a fight, hence mothers becoming outrageously short in iodine).

If iodine deficiency was not an issue, I would not see the results in my patients I have seen from giving them a simple combination of iodine and potassium iodide, in doses that would make physicians uneducated in proper human nutritional needs squirm.

The other problem with seaweeds is that no one knows, batch to batch, how much iodine is in it. I was told by a gentleman at http://www.naturespiritherbs.com/ that the iodine content of sea vegetables can vary up to 10-fold! Hard to dose properly with a "food" that's for sure.

In short, I disagree, and I believe that NO ONE should be getting Armour, Synthroid, or any other thyroid hormone UNTIL an iodine deficiency and autoimmune thyroid condition (likely caused by gluten and/or EFA deficiency) has been properly ruled out. EVERY "hypothyroid" (either lab diagnosed or symptomatic) has come up deficient on the 24-hour iodine sufficiency test. On this I won't budge.

The human body isn't so often screwed up, it's us who are screwing it up. Giving hormones willy-nilly only masks the problems, which are still smoldering under the surface, and will rear their ugly head sooner or later.

I likes my iodine...

Steve Liberati
05-07-2007, 03:50 PM
Fair enough Garrett. I was more spitting out what I have learned on the topic..not making statements that I believed were rock solid conclusions. In fact, I'm glad you wrote that post as it sparked my further interest into the iodine issue. I'm very confident that if you said it, there is much truth to it and worth further investigation. Good stuff, thanks for the info!

Allen Yeh
05-07-2007, 05:05 PM
I'm in Steve I'll take my resting temperature upon rising for a week or so. I'm curious because when they took my temp. when I went to give blood the other day it was 97.2 which is lower than usual. I'm typically lower than the average but I don't recall getting such a low reading when I haven't been sick.

Now the trick is to remember doing this at 4:30-5 am in the morning! haha!

Nikki Young
05-07-2007, 05:06 PM
Garrett, would you be able to explain in a bit more detail how gluten intolerence and/or an EFA deficiency plays a role in effecting the thyroid?
When you say EFA, i presume you're leading more towards an Omega3 deficiency, over Omega6?

Steve Liberati
05-07-2007, 05:43 PM
Sorry not Garrett and not sure about gluten intolerance, but i know the metabolism of fats and absorption of EFA's are very important functions of the thyroid. Insufficient T4 to stimulate fat metabolism can lead to Hyperlipidemia, or elevated cholesterol. Without the benefit of cardio protective nutrients from essential fatty acids, the increase of cardiovascular disease greatly increases, not to mention a slow, weak thyroid gland. Inadequate T4 in the cells has a negative effect on oxygen consumption as well. Excess oxygen results in an increase in the oxidation of lipids (fats) and free radical damage. Increased oxidation of the low-density lipoprotein (LDL) form of cholesterol, often referred to as "bad" cholesterol, has been identified in hyperthyroidism and hypothyroid states. But before worrying about any of this...the first place to start is with the adrenal gland as Garrett suggested. Iodine deficiency is usually the problem, unbeknown to most people... causing an under active thyroid and other fixable problems.

Garrett Smith
05-07-2007, 06:48 PM
I'm rushing to go home, but I wanted to give you something to play with...

Go to PubMed and do searches of "EPA thyroid", "DHA thyroid", "gluten thyroid", and "celiac thyroid".

That should give you plenty to look at, and save me a little time... :-)

And yes, I'm talking about an O-3 deficiency. You could even do a search of "GLA thyroid" while you're there, that may play a role too...

Stuart Mather
05-07-2007, 10:08 PM
Interesting about the iodine Garrett. Do you think there is a safe supplementary amount of the potassium iodide/iodine combo if I have no idea if I'm iodine deficient or not. I take a kelp tablet a day and use sea salt moderately. I can't imagine feeling healthier than I do, but if I was iodine deficient, some basic supplementation should produce noticeable improvement shouldn't it?


Nikki Young
05-07-2007, 11:07 PM
Thanks Steve! That was a good explination :)

Thanks Garrett! I've read a few links on pubmed from my searches but nothing that has yet answered my above questions.. they are just making me more confused :o I'll keep reading a few more though, am keen for your reply tomorow!

Allen Yeh
05-08-2007, 03:51 AM
May 8, 2007
Temp: 96.3 (I think the digital thermometer is broken....)

Everyday is a feed day for me, my fasting hours vary from 15-18 hours typically.

Steve Liberati
05-08-2007, 04:35 AM
May 8, 2004
Temp: 96.4
Previous day: Fast day

Yep time to invest in a new digital thermometer as well...

Garrett Smith
05-08-2007, 06:49 AM
I'm going to try to be succinct about the gluten/thyroid connection.

Gluten causes leaky gut, which then leads to excessive stresses on the immune system and autoimmune conditions with time.

The excessive stresses on the immune system wear down the adrenals, and the adrenal function is heavily linked with thyroid function. After progressing past that, we get into autoimmune disorders, of which the thyroid is a big participant in.

As for O-3s, without enough of them, or the right ratios, all communication within the body is compromised. This is why a lack of fish oil can cause so many different (seemingly unrelated) problems in the body, and appear like the panacea to "fix" so many problems. The thyroid is just one of them.

As I mentioned before, men don't tend to have as much of an issue with iodine. You may or may not have an issue--although I'd place my bet that you would be at least slightly low. The first issue is always making sure that autoimmune thyroid conditions are not present, both through history and previous/current labs. An autoimmune condition simply warrants a different approach than normal.

There way I suggest pursuing this issue is the 24-hour "loading" iodine sufficiency test. You take 50mg of iodine/potassium iodide (Iodoral) and then collect your urine for 24 hours. The amount of iodine you excrete of that 50mg is indicative of your body's hunger/need for iodine. Sufficiency is noted as being a >90% excretion (more than 45mg comes out in the urine). Knowing that, we can estimate the time necessary to be on a daily loading dose, and follow up with another test around that time. After sufficiency is reached, the daily dose is reduced to 12.5mg. If one wants to do whole food sources of iodine, as in significant doses of sea vegetables (one kelp tablet may contain ~500mcg of iodine, hardly enough!), that can be done after sufficiency is reached. This is the approach I would suggest.

Some have simply taken the loading dose for a period of time (3-4.5 months, let's say), assumed that sufficiency was reached, and then gone to the maintenance dose.

As a male, I wouldn't "go by feel" on this issue, as you will likely not notice huge changes unless you have significant iodine deficiency (easily found out through the test, which costs less than two bottles of Iodoral).

I do consistently notice that I do not get cold when everyone else is, and that reducing bodyfat has become ridiculously easy since I've been taking the Iodoral. I also consume a decent amount of sea vegetables (I'm going to submit my seaweed salad recipe to the PMenu).

Stuart Mather
05-08-2007, 07:19 AM
Some have simply taken the loading dose for a period of time (3-4.5 months, let's say), assumed that sufficiency was reached, and then gone to the maintenance dose.

Sound's the easiest way. Maintenance dose is 12.5 mg iodoral right? So if I'm not iodine deficient and I take the 3 month loading dose, is it going to do me any harm?
Btw. I know it's been discussed ad infinitum here, but I'm still a bit confused about how much EPA/DHA to consume. I take 15ml fish oil daily. Is that enough? I keep noticing cautionary mention of O- 3 overconsumption.


Robert Allison
05-08-2007, 07:20 AM
Good info, Garrett.

I also consume a decent amount of sea vegetables (I'm going to submit my seaweed salad recipe to the PMenu).

I look forward to trying it out; I'll try anything to improve the taste of that stuff. I've always thought that most recipes centered around sea vegetables were based on a dare. ;)

Also, a couple of posters on this thread have mentioned sea salt as a source of iodine. While natural sea salts do have other positive qualities, they provide iodine only in very small (trace) amounts. While sea vegetables are a better source, they have limitations as well. In addition to what Garrett alluded to above, Dr. David Brownstein has found that some kelp supplements may contain toxic levels of arsenic or halides.


I'm not sure if other sea vegetables have the same issues or if this just applies to kelp.

Allen Yeh
05-09-2007, 06:19 AM
May 9, 2007
Temp: 97.1

Everyday is a feed day for me, my fasting hours vary from 15-18 hours typically.

Garrett Smith
05-09-2007, 06:49 AM
I keep forgetting to bring my thermometer home.

I shoot for 2400mg of total EPA+DHA a day. The EPA+DHA is the only number I go by, not by mL or g of "fish oil". I figure that amount is sufficient, as I strive quite hard to only eat properly sourced animal products (which have at least close to the proper O-3 to O-6 ratio).

For example, with my concentrated liquid fish oil and concentrated CLO (for the A & D), I can get my 2400mg in 1.25 teaspoons of total oil, along with 500IU D and 5000IU A.

To get the same amount of EPA+DHA in the basic Kirkland capsules, one has to take ~8 capsules, and they don't get any A or D.

If one is doing around the amount I suggest, there is very little likelihood of "overdoing" the fish oil.

Brad Hirakawa
05-09-2007, 06:57 AM
What are some of the symptoms of overdoing fish oil? Mostly GI issues?


Garrett Smith
05-09-2007, 03:50 PM
Brad, here's something I found cruising Google under "overdose fish oil symptom": http://ezinearticles.com/?Overdose-Symptoms-of-Omega-3-Oil---Watch-Out-for-Overdose-Symptoms-of-Omega-3-Oil!&id=488559

Steve Liberati
05-09-2007, 04:10 PM
May 8, 2004
Temp: 96.4
Previous day: Fast day

Yep time to invest in a new digital thermometer as well...


Today May 9th
Temp: 96.9
Previous day: Feed day

Allen Yeh
05-10-2007, 04:00 AM
D'oh I was late getting up today so I totally forgot about taking my temperature.

Stuart Mather
05-11-2007, 03:01 PM
Up and down between 95.9 and 96.2 for the last four mornings.

And Garrett, my wife and I started taking 5 drops of lugol's solution daily a few days ago. I haven't really noticed any difference, but Dana's chronically cold hands and feet suddenly became warm on the second day and have remained so. Do I really have to take the loading dose for a couple of months?

Garrett Smith
05-11-2007, 04:12 PM
I need to remember to bring home my dang thermometer!!!

The loading dose won't hurt you in any way, the solution is cheap, so I'd say you have several options:

Stay on it for several months.
Test in several months to find out if you (or your wife, who is obviously benefiting) have reached sufficiency.
Quit the loading dose "early" and hope that you eventually reach sufficiency on a daily maintenance dose. Yes, this is an "every day, for the rest of your life" kind of supplement (unless you live by the ocean AND start eating a whole bunch of sea veggies).

It will likely take your wife significantly longer to reach sufficiency than you, however, without testing, we'll never know.

That's great about your wife's results so quickly! I live for that stuff.

Trygve Lunde
07-26-2009, 04:01 AM
great post, ive been fasting alot and also doing high fat/low calorie diet and ive been struggling with rash on my left arm and in my head for 1-2 months now. I have been searching all over and i came across thyroid and i took my tempeture. The last two days now its been a bit under, so my thyroid is slacking. Thanx for all the info, gonna cut out the fasting and eat a bit more. thanx again

Mike ODonnell
07-26-2009, 12:01 PM
Add some carb up days as well....low carb all the time can lower metabolism through the leptin pathway.

Trygve Lunde
07-26-2009, 12:23 PM
ahh ok, thanx

Trygve Lunde
07-30-2009, 01:23 PM
is there a article or something about carb up days? what its good for etc.

Derek Weaver
07-30-2009, 08:00 PM
I've seen you post a while back on Lyle's forums. Look up the EOD refeed thread in the general dieting section for the best, and longest free source of info.

In general they give a good jolt to all the hormones that tend to plummet during very low carbs/dieting.

Trygve Lunde
07-31-2009, 11:51 PM
I've seen you post a while back on Lyle's forums. Look up the EOD refeed thread in the general dieting section for the best, and longest free source of info.

In general they give a good jolt to all the hormones that tend to plummet during very low carbs/dieting.

Thanx a ton my man.. im struggling a bit now u see. Took my morning temperature today and it was 95.54

Derek Weaver
08-01-2009, 08:40 PM
You need to refeed and eat normally for at least two weeks. By eat normally, at least 100 grams/carbs per day and at maintenance at least.

Trygve Lunde
08-03-2009, 11:39 AM
ok, thanx :D

Mike ODonnell
08-03-2009, 08:54 PM
I recently went a whole day eating high carb, low fat...pancakes with syrup....low fat ice cream....I sweat my ass off for the whole day/night.

If you can't feel your body temp increasing 3-4 hours after a high carb meal....you didn't eat enough carbs.

Trygve Lunde
08-08-2009, 04:57 PM
hehe ive tried and it worked :) cant sleep anymore at night tho :( since its to hot but ill take that instead of a cold low energy guy.

Trygve Lunde
08-08-2009, 05:21 PM
i still have one problem tho and that is the rash on my left arm, and im also really really really itching in my head. Im eating clean, whole foods only. I have no idea what it can be

Derek Weaver
08-08-2009, 05:33 PM
Go to a dermatologist.