Low Body Fat – The Tipping Point

On the contrary, I think calipers are a good way to measure bf. Only better is weighing in water (rare and expensive) and full body MRI (expensive). There is really nothing else. Simple electronic methods are very innacurate.

Accuracy with calipers is however related to the skill of the person and the # of points, and the correlation used.

To my knowledge, essential bf for men is about 2-4%. Clarence Bass is the expert on achieving low body fat, pretty much has been for 30 years.

I agree with you, if you dont want to carry enough food, you need to have some fat reserves. But a 160 lb person at 6% body fat still has several lbs to spare. A bigger problem is that you will lose muscle too anytime you starve yourself. And the lower the bodyfat % goes, the higher the ratio of muscle /fat lost will generally be.

My bf was tested via hydrostatic weighing. Calipers at best have a 3% error. You can't measure body fat with an MRI. You must mean DEXA which is a bone density scan. My min 5% comes from the medical community.

I think if you research it a bit, you might find that not only can you measure bodyfat with a full body MRI, but it is regarded as the most precise way. It can precisely determine the volume of fat stores under the skin, as well as visceral, intramuscular, etc. More of a leading edge research thing really currently, cost and access makes it impracticle for 99.9% of people. Since a normal MRI looking for soft tissue damage only is billed at about $1500, I wouldnt want to know what something complicated like body composition analysis would run.

Hydrostatic weighing is also not without its own difficulties and imprecision, generally related to the lung capacity and ability of the subject to expel air in lungs.

Ill add that I have a biomedical research facility affiliated with a major university near me that does full body MRI composition analysis for all their studies. They frequently solicit volunteers for diet/nutrition studies. They actually pay but you have to eat all your meals there for the duration of the study.

I know several persons that have participated in these studies. One may have had his life saved because the initial scan showed a malignant tumor in one of his kidneys, which was promptly removed the next day.

Looks like you're correct about the MRI thing, but I don't see it being used as a body comp tool any time soon.

Every method has some percentage of error since they're all just estimations.

Hydrostatic weighing – 1-1.5% and $30-50/test.
High quality Calipers – 3+% and $200-400/set
Air displacement – 3+% and $40/test.
BIA – 5+% and no idea on cost of a commercial machine
DEXA – 1% and $50+/test

Now that we have that out of the way, we should get back on topic.

besides being colder natured, another downside to low bodyfat is comfort. Your butt is bony and it hurts to sit on hard non-padded items. Your hips and spine are bony as well. One might end up needing a heavier, more comfortable pad than when you carry your own built-in padding.

Personally, I don' have a bony butt. Low body fat doesn't necessarily mean bony.

Chris,

Care to share a typical week's diet? I say diet in the traditional sense of food consumed, not the overused term to describe fad diets, unhealthy food practices, starvation, fasting, etc. I'm aware your food intake is a direct response to a lifestyle change, not a season or trend.

I'm interested in what you intake in the week to support your level of activity. Is it affordable, simple?

"Personally, I don' have a bony butt. Low body fat doesn't necessarily mean bony."

I think it's pretty unlikely that people who do a lot of trekking, bicycling, running, and that sort of thing will have bony butts. I don't have a lot of fat on me, but I don't have a bony butt :)

I've certainly managed to build some butt padding, but I've really never been about 8% bodyfat or so. I also have some experience with being cold, as well as some experience, recently, with NOT being cold.

I think there are some things that may be overlooked in this discussion so far. Notably, the "brown fat" cells that are, if I recall correctly, similar in form to muscle cells, but exist subcutaneously and primarily exist to burn fat to generate warmth. We're born with a lot of them, but they dwindle significantly by adulthood. Whether that's a natural occurence or a result of our modern, centrally-heated environments has yet to be studied. Whether we can increase their number in adulthood is also not known to me.

However, it makes me think about the Seneca culture that existed in my region before they were all rounded up etc. It's recorded that many Seneca men would remain rather lightly clad, in the outdoors, throughout the year. The child-rearing practices of the Seneca are also interesting, particularly the fact that mothers would bathe their children (from infancy) in icy cold water on a daily basis to inure them to the cold. Similar cases of cultures producing highly cold-resistant people aren't too hard to find.

So my question, as a very-lean person who was raised in abundant warmth and tolerated the cold better than my peers (probably from walking everywhere year-round) but nowhere near as well as many other humans, was "can I increase my cold tolerance through some sort of conditioning?"

The answer has definitely been yes. Last winter I started doing any short walks near the house in the snow barefoot (never long enough to go totally numb) and twice a day (immediately upon waking or before sleeping), standing out on the back porch in just boxers and slippers for 10 minutes, no matter how cold (and we do get -10 windchills). Add cold showers on top of that (which saw my eczema dissapear, funny enough) and intentionally under-insulating myself for walks of known duration, and before I knew it my cold tolerance was vastly improved. The first post-thaw plunge into the lake this spring, usually a trial, was just pleasant. I felt a lot more "free" all winter without having to be as dependent on external sources of heat.

My appetite did see an increase during this period. I was following a roughly-paleo diet with intermittent fasting that was often in the very-low-carb range. I found that I was consistently warmest fasting most of the day and limiting my eating to a 3000+ calorie high-fat-and-protein meal in the evening before bed. Keeping the insulin downregulated seems to have been key, because if I ate anything carby I found myself eating a LOT more to keep just as warm. Most of my exercise was the long-term low-intensity or very quick high-intensity sort, so carbs weren't really necessary. As it warmed up and I started running and cycling more, increasing carb intake has seemed to be best. There's no rule that says we should eat the same way all year long, after all.

Any given person has tens of thousands of extra fat calories in storage. Even if they're not enough to insulate you (like mine) conditioning the body to burn them freely to generate heat and eating in a way that doesn't inhibit that process (as in keeping insulin low) seems to be a very doable thing.

"Any given person has tens of thousands of extra fat calories in storage. Even if they're not enough to insulate you (like mine) conditioning the body to burn them freely to generate heat and eating in a way that doesn't inhibit that process (as in keeping insulin low) seems to be a very doable thing."

Agreed. Mountaineers do exactly that. :)

" Most of my exercise was the long-term low-intensity or very quick high-intensity sort, so carbs weren't really necessary."

This puzzles me a bit. Everything I've ever read on the subject indicates that some carbohydrate is necessary to "burn" fat in a metabolic process known as the Krebs Cycle. If carbohydrate is not present in an amount appropriate to the intensity of the exercise, protein will be converted by the liver to provide it. What I am wondering is whether you were converting muscle/dietary protein to provide the necessary glucose to metabolize your fat.

Eugene-

I recently started eating a primarily vegetarian diet so I don't have a consistent rotation of meals developed yet. I can tell you how I eat on average though.

7 AM (wake up) – 400-600 cals
9 AM snack – 200-300 cals
11:30 AM lunch – 400-600 cals
2:00 PM snack – 200-300 cals
4:00 PM snack – 200-300 cals
6:30 PM dinner – 400-600 cals
8:30 PM snack – 200-300 cals

Average daily intake 2000-3000 cals. Also, I will eat a little more careless usually once a week and might take in 4000 cals (or more).

My activity level since I retired from corporate life is considerably less than it used to be. I walk 3-5 miles daily, run 5-8 once a week, and might bike 10-15 miles (commuter) one day. I also do 20-40 pullups, 50-100 pushups, and 15-20 handstand pushups daily. I do yoga or general stretching a couple times a week as well. That's on average again.

My weight is consistently 138-140 when I get up in the morning varying mostly based on how heavy my meals were, how hydrated (or over-hydrated) I am, and how regular my BMs are.

I'm not nearly as versed in this subject as some here, but I figured I'd chime in.

My whole life I've been "lean." I'm 5'11" and the highest I ever weighed was 148lbs when I was beyond sedentary and drank a gallon of dark beer a night to chase a large pizza dinner for about 6 months straight. (That 150 is just so dang elusive!). Since then I've taken up backpacking and rock climbing which has seen me drop to 145lbs and my functional strength and muscle mass increase dramatically. BF% I'm not sure of but based on my build I'd estimate 15% at my max and somewhere between 5-10% at my fittest.

I also grew up and live in the deserts of AZ where our winters rarely see 30F nights and only a handful of 50F or colder day time highs. I've also lived in Boston during some of their snowiest and coldest winters on record since the 70s so I have a fair bit of anecdotal experience in the cold.

So with that out of the way:

Chris, you gave one specific example where you were cold. The weather was in the 60s and raining. And one where you were warm, in the teens. The humidity probably played a huge role in that. Many people (Skurka I know for one) all claim that 30s and rainy is by far the most miserable weather on the planet. The liquid moisture just saps the heat from you. 60s aren't much better…that said I still feel your chilled pains.

When I first started backpacking I was getting cold constantly. Some things I've changed (eating habits before bed) which helped marginally. However the more I expose myself to the cold the better I tolerate it. This is consistent with my time in Boston. I was able to survive those bitter winters with just a hoody, l/s tee, and thick leather jacket with jeans for my legs. I didn't have all my nice technical gear I do now. I did ok, by no means pleasant but I could be out all day. This wasn't the case at first though. It took me a solid winter first of living out there before I simply "got used" to it. Also for the record that second winter I had dropped to an unhealthy 125lbs but with better cold tolerance.

The more pressing matter though is the reserve energy you speak of. I've always had digestive problems, nothing serious just enough that eating isn't considered pleasurable for me. As such I can often forget to eat for a day or more. When this happens though, I'll wake up and have no energy. I mean literally zero. To the point where crawling out of bed to make food requires a massive amount of willpower. As soon as I do though, I start to feel better in a half hour or so.

Clearly diet becomes a huge component when you drop below the 10% BF (for males, sorry ladies I don't know what would be comparable for you). You are spot on to be worried about reserves.

I think "food training" comes into play as well. Even when I do eat, I rarely exceed 2500 calories in a day, no matter what my energy expenditure. I also possess extremely efficient muscles (I could leg press 450+lbs and weighed 130lbs before I got a car and my legs went to hell…with no specific leg/weight training, just walking). A lot of this comes from having a kinesthesiologist for a father that specifically researched neuron utilization in muscles. We can discuss the ethics of using your offspring as subjects some other time.

So if your metabolism is using 6+k cals a day you probably need to retrain it suffice at much lower levels. I don't know of any specific way to do so, but considering the human body's adaptability just "starving" it may be enough to reprogram your metabolism and muscle neurons assuming you don't have some underlying endocrine issue like hyperthyroidism.

Sorry, it's late and I'm a bit rambly and not as precise as could be. Just wanted to throw my own 2c into the fray. Also to ape the others, congrats on the fitness, you're at quite an impressive level, it motivates me to get back into the fray!

I think some of the coldness is resting pulse, I have similar issues, especially when hiking with others that I need to bring a lot of extra clothing since I'm not making much of my own heat. I'm not as fit as I was a year or so ago , when my pulse the day after I did a 50k was in the low 40's (I guess that meant I had recovered ?). However, when on my own, and if I stay clean (jump in a lake to rinse of sweat) heat isn't much of an issue, just when I am with others and we are moving it's real apparent.

Mark Twight in his extreme book Extreme Alpinism talk of eating lots of fat, and of feeling warmer by drinking olive oil (I think it was Yvon Chouinard that mentioned the olive oil making him warmer). Shakelton's group ate high fat and lived on ice for a year.

I eat mostly Primal / Paleo (but not as much strict as I once did) but I eat a lot of fat. I've found I can keep going pretty well on the fat at a decent intensity. In fact, in Ultra's I opt for more fat / less carbs primarily as my stomach reacts better to the fat.

I am sure there is more to it, but it seems like , if you aren't putting much fat in your body, your body wants to horde it. If you put some fat in , your body says ok, we can use it.

"I think some of the coldness is resting pulse"

What, do you think your heart is the only thing in your body that generates heat?

"I am sure there is more to it, but it seems like , if you aren't putting much fat in your body, your body wants to horde it. If you put some fat in , your body says ok, we can use it."

True. That's why people on starvation diets end up replacing muscle with flab. Muscle is useless for insulation, and you don't get much energy from metabolizing it, since it's mostly protein. So if you starve yourself by eating infrequently, or like most americants you eat huge portions infrequently, your body adapts by building fat stores to tide you over until the next meal. Eat frequently, and your body adapts by burning it off.

Sugar will warm you up also, but not for long. Fat takes longer to metabolize than straight carbohydrates like starch, sugar, and alcohol, so it keeps you warm for a longer period. Olive oil has a lot of fat, and it's fat that we're adapted to burn, so it's an excellent choice for backpacking. Plus if you make sure that you get good olive oil, it tastes good. :)