cardio before breakfast?

In the summer months I am on my bike almost every day, but in winter it’s the elliptical in the basement for my cardio. I don’t do a lot, just 30min, while watching something or other on netflix or hulu (just finished my Buffy rewatch, in fact). I recently have resolved to try and do my cardio to the morning before the kids wake up, which then raised the question of whether it is better to do it before or after breakfast. A couple of years ago, a NYT article made the case that you burn fat faster when fasting:

Only the group that exercised before breakfast gained almost no weight and showed no signs of insulin resistance. They also burned the fat they were taking in more efficiently. “Our current data,” the study’s authors wrote, “indicate that exercise training in the fasted state is more effective than exercise in the carbohydrate-fed state to stimulate glucose tolerance despite a hypercaloric high-fat diet.”

At the same time, the fasting group showed increased levels of a muscle protein that “is responsible for insulin-stimulated glucose transport in muscle and thus plays a pivotal role in regulation of insulin sensitivity,” Dr Hespel said.

In other words, working out before breakfast directly combated the two most detrimental effects of eating a high-fat, high-calorie diet. It also helped the men avoid gaining weight.

The study quoted by the article has some differences from my situation – it was a deliberately high-intensity workout, and the subjects were eating a high-fat, high-calorie diet. So would the same advantages hold for me, whose cardio workouts are light to moderate, and with a pretty balanced diet? The conventional wisdom now seems to be that working out while fasting in the morning does let you burn fat more efficiently.

However, an article at bodybuilding.com a year later says otherwise. To be blunt, the biochemical explanations sound as hand-wavy as everything else I ever read in these health magazines. But here’s the key argument:

True, the research does show that fasted cardio can increase fat utilization during exercise compared to performing cardio in the fed state. Except this only occurs at very low levels of training intensity.

During moderate-to-high intensity levels, the body continues to break down significantly more fat when fasted compared to after you’ve eaten.

So far, so good. Unfortunately, the rate of breakdown exceeds your body’s ability to use the extra fatty acids for fuel. In other words, you have a lot of extra fatty acids floating around in the blood that can’t be used by working muscles.

Ultimately, these fatty acids are repackaged into triglycerides post-workout, and then shuttled back into fat cells. So you’ve gone to excessive lengths…only to wind up at the same place.

Horowitz and colleagues (2) found that when trained subjects exercised at 50 percent of their max heart rate, an intensity that equates to a slow walk, there was no difference in the amount of fat burned–regardless of whether the subjects had eaten.

These results held true for the first 90 minutes of exercise; only after this period did fasted cardio begin producing a favorable shift in the amount of fat burned.

So unless you’re willing and able to slave away on the treadmill for a couple of hours or more, fasted cardio provides no additional fat-burning benefits, irrespective of training intensity.

Fasted cardio makes even less sense when you take into account the impact of excess post-exercise oxygen consumption. EPOC, commonly referred to as the “afterburn,” represents the number of calories expended after training. Guess what? Eating before exercise promotes substantial increases in EPOC (3).

And guess where the vast majority of calories expended in the post-exercise period come from? You got it, fat!

On top of everything, fasted cardio can have a catabolic effect on muscle. Studies show that training in a glycogen-depleted state substantially increases the amount of tissue proteins burned for energy during exercise (4).

Protein losses can exceed 10 percent of the total calories burned over the course of a one-hour cardio session — more than double that of training in the fed state (5).

The article summarizes all of this as: At best, the effects on body composition won’t be any better than if you trained in a fed state; at worst, you’ll lose muscle and reduce total fat loss.

So, I think I’ll eat first and workout after. But none of this helps me actually get out of bed an hour earlier to do the workout before the kids get up!

Get well soon, Ubu

I can’t believe it took me a week to notice – apparently Ubu Roi had a (thankfully mild) stroke last week. He seems to be recovering well but it is still a terrifying thing to contemplate. He’s a lucky man and I am glad he is doing okay, and will pray for his continued and complete recovery.

It’s a good excuse to post Stroke Stick Guy as a public service – the first few hours of a stroke are the most critical. My PhD dissertation was in Diffusion MRI (one of the main tools to detect ischemia) so it’s a topic I’ve thought quite a bit about. My best wishes to Ubu and his family.

even more exercise that I should be doing

My workout regimen is an elliptical machine and a Bowflex at home. At least, I have the machines, but I’ve been slacking of late in actually using them. My intention is to follow the schedule:

  • M, W, F: elliptical for 30 min
  • T: Bowflex for chest and back
  • R: Bowflex for arms and shoulders

Unfortunately the time I set aside for the above tends to get eaten by work or family stuff, so I need to do a much better job of adhering to this. My saving grace is that no matter whether I’ve worked out or not, if the weather is good we go out biking as a family in the early evening, which is a nice 6 mile circuit with some big hills. I look at this as recreation and not exercise, but it definitely is a workout (especially since I’m pulling a trailer with 40lbs of 5-year old in it).

However I do need to supplement this with some sort of daily routine. So I was glad of this lifehacker post which reminded me of the 100 Pushups program that I long-ago stated I intended to pursue, along with new programs I hadn’t heard of before for similar at-home exercises. Here’s the list:

100 pushups
150 dips
200 situps
200 squats

There’s also a 25-pullups program in the works but lets start with the above at least. I need to figure out the best way to integrate these into my week. I havent even read them in detail yet, so this is sort of a placeholder post while I develop a plan. Suggestions and ideas are welcome!

I invite critique and suggestions!

diet, cholesterol, and heart disease skepticism?

I’m involved in a debate over diet and health over at Dean’s and in the course of that debate, was encouraged to read a paper by Corr et al. that suggests low-fat diets are essentially useless for reducing heart disease. This post started out as a comment but it grew enough to warrant a post in it’s own right. So, let’s look at what the Corr paper is actually saying, shall we?

The international bodies which developed the current recommendations based them on the best available evidence[1-3]. Numerous epidemiological surveys confirmed beyond doubt the seminal observation of Keys in the Seven Countries Study of a positive correlation between intake of dietary fat and the prevalence of coronary heart disease[4] although recently a cohort study of more than 43,000 men followed for 6 years has shown that this is not independent of fiber intake[5] or risk factors. The prevalence of coronary heart disease has been shown to be correlated with the level of serum total and low density lipoprotein cholesterol (LDL) as well as inversely with high density lipoprotein.

So, high intake of dietary fat indeed has a positive correlation for coronary heart disease. Corr is conceding this at the very start!

Further, coronary heart disease is also indeed associated with high LDL and low HDL. So far I am not seeing any Cholesterol Conspiracy here… the ADA seems to be right on the ball.

So, we’ve already established that CHD is associated with high fat, high LDL, and low HDL. So, what’s left to argue about?

As a consequence of these studies, it was assumed that the reverse would hold true: reduction in dietary total and especially saturated fat would lead to a fall in serum cholesterol and a reduction in the incidence of coronary heart disease. The evidence from clinical trials does not support this hypothesis.

Hmm. Two sentences here. one about a reasonable inference from the conceded association between fat and LDL with CHD. But ok, let’s call the question of whether teh reverse is true, Question A – “does reducing fat and LDL in the diet reduce CHD?”

And then another sentence, about evidence from clinical trials not supporting that inference. What about those clinical trials, exactly?

It can be argued that it is virtually impossible to design and conduct an adequate dietary trial. The alteration of any one component of a diet will lead to alterations in others and often to further changes in lifestyle so it is extremely difficult to determine which, if any, of these produce an effect. Dietary trials cannot generally be blinded and changes in the diet of the ‘control’ population are frequently seen: they may be so marked as to render the study irrevocably flawed. It is also recognized that adherence to dietary advice over many years by large population samples, as for most people in real life, is poor and that the stricter the diet, the worse the compliance.

Ah. so the available evidence from clinical trials is fundamentally suspect to systematic error. Fair enough. So, any conclusions we make from them should be tempered with that, right?

(long analysis of clinical trials in literature follows)

The message from these trials is that dietary advice to reduce saturated fat and cholesterol intake, even combined with intervention to reduce other risk factors, appears to be relatively ineffective for the primary prevention of coronary heart disease and has not been shown to reduce mortality.

OK, so the trials focusing on low-fat diets alone didn’t show any primary prevention benefit. Well, see caveat above, right? (and Corr’s noted exception about the MRFIT study…)

However, what about secondary prevention?

well, good! But still, is there some reason that maybe we aren’t seeing better results here? Is diet necessary, or sufficient? Let’s look at studies that not only remove fat, but also add HDL:

The first successful dietary study to show reduction in overall mortality in patients with coronary heart disease was the DART study reported in 1989[20]. The three-way design of this ‘open’ trial compared a low saturated fat diet plus increased polyunsaturated fats, similar to the trials above, with a diet including at least two portions of fatty fish or fish oil supplements per week, and a high cereal fibre diet. No benefit in death or reinfarctions was seen in the low fat or the high fibre groups. In the group given fish advise there was a significant reduction in coronary heart disease deaths and overall mortality was reduced by about 29% after 2 years, although there was a non-significant increase in myocardial infarction rates. The reduction in saturated fats in the fish advice group was less than in the low fat diet group and there was no significant change in their serum cholesterol.

Finally, the more recent Lyon trial[21] used a Mediterranean-type of diet with a modest reduction in total and saturated fat, a decrease in polyunsaturated fat and an increase in omega-3 fatty acids from vegetables and fish. As in the DART study there was little change in cholesterol or body weight, but the trial was stopped early following a 70% reduction in myocardial infarction, coronary mortality and total mortality after 2 years.

In other words, adding HDL to your diet helps a lot, whereas reducing polyunsaturated fat (or just increasing fiber) still doesn’t seem to do anything. We’ve established that a modest increase in HDL can help. But have we established that a modest reduction in LDL will not help?

Unfortunately, the design and conduct of these trials are insufficient to permit conclusions about which polyunsaturates and other elements of these diets are the most beneficial. The long term effects of these trials[20,21] and the compliance with the dietary regimes remain to be seen.

So, we don’t really know if these studies answer that question. It’s possible that lowering LDL has a longer-timescale benefit than increasing HDL. These studies don’t answer the question either way, because of the limitations Corr concedes – certainly we haven’t proven that lowered LDL is not genuinely helpful yet.

Anyway, how much LDL was really reduced anyway?

An important aspect of the lipid-lowering dietary trials is that on average they were only able to achieve about a 10% reduction in total cholesterol. The results of recent drug trials have demonstrated that there is a linear relation between the extent of the cholesterol, or LDL, reduction and the decrease in coronary heart disease mortality and morbidity, and a significant effect seen only when these lipids are lowered by more than 25%[23].

Ahhhh. Corr goes on to quote a bunch of studies that show frankly awesome improvements in mortality using drugs to lower LDL by 25% or more.

(in other words, definitively proving that lower LDL does indeed reduce heart disease. We just answered Question A from above).

So, let’s summarize:

conceded by Corr at the outset:
– increased HDL reduces CHD.
– increased fat increases CHD.
– increased LDL increases CHD.

dietary trials:
– somewhat lowered LDL does not reduce CHD.

drug trials:
– significantly reduced LDL does reduce CHD.

caveats:
– dietary trials have systematic errors.
– long-term trials on reducing LDL have not been performed.

special note: The MRFIT trial follow up focused on reducing LDL diet alone, and did show reduced myocardial infarctions over a longer term.

My conclusion from this would be that a. increase HDL now for immediate benefit, and b. reduce fat and LDL in my diet for long term benefit. Seems obvious enough, and fully in accord with what the ADA recommends.

Corr’s conclusion?

diets focused exclusively on reduction of saturated fats and cholesterol are relatively ineffective for secondary prevention and should be abandoned.

umm.. what?!?!

This is where they cross over into vaccines-autism and flouridated water territory, frankly.

What would have made the Corr paper immeasurably stronger would have been for them to devise an experiment that would answer these questions and fill the gaps. That’s always my challenge to these self-styled “skeptics” of the scientific consensus. What’s the experiment you propose? What would you do to make your case?

That’s how science works. Theory drives experiment, experiment refines theory, and back again. If your claim is that available evidence (in this case, clinical trials) don’t support the contention, that’s not enough. You need to come up with an experiment that actually refutes the contention. Formulate your hypothesis and test it! Anything else is just nitpicking from the sidelines, which is how most of these agenda-driven meta-analyses end up reading.

Frankly, I am very much eager to be able to dispense with the low-fat, low-cholesterol crap. Here’s why in a nutshell.

So please, Dr Corr and anyone other “cholesterol skeptics” out there. Show me the proposal for your experiment, and I guarantee you the fast food industry will show you the money.

basic health – baby steps

I’ve actually been stereotypically awol in blog posts in my “Fitness” category. But there actually has been recent movement on that front; we bought an elliptical machine which I’ve been making regular use of (averaging 4x a week, 25min) and I got my cholesterol and vitamin D levels checked as part of a basic checkup. I’ve started taking multivitamins, and am taking daily 5000 IU of D3 since I’m highly deficient. Plus my cholesterol is a normal-but-high 169 and my HDL is a baseline-minimum-normal 40. So, there’s room for improvement, and I’ve started reducing my fast food accordingly (but not enough).

I haven’t totally changed my lifestyle around but I am making these initial, positive steps (exercise, diet, and supplements). In a couple of months I have a follow up and lets see what effect it has.

Now, I’m going to go to a conference for a week, and get very little sleep, no exercise, and eat junk the whole time. sigh. I’ve got my vitamins, though!

Incidentally, this piece in the Times about the real value of exercise was illuminating.

(haven’t used the Wii much at all of late. Need to get back into that, at least doing the pushups and situps, again, too. After Stockholm.)

Woot! Wii Fit in stock at Amazon.com

I’ve been trying to get a Wii Fit from the local Target for weeks now but just could not get my hands on one. It’s as popular as the Wii itself was when it first came out; now they routinely have 3-5 Wiis in stock but the Fit is sold out within minutes of new stock. On a lark, I gave Amazon a shot this morning and found to my astonishment that they had them in stock! I grabbed one immediately and it arrives on Wednesday. I look forward to being serially abused by my new electronic master forthwith.

Wii Fit! Woot!

wiifit

not the orange popsicle kind

push-upFew things mark seriousness of intent as much as adding a category to your blog. So take the addition of the “fitness” category here at Haibane.info for the momentous event it is. I’m in reasonable shape – I am 5′ 8″ and I weigh 150 lbs. That’s a Body Mass Index of 22.8 which is solidly in the normal range. I used to lift weights in college and still retain some of that mass. I also was an avid bicyclist for a time. However it has been about 7 years since I last went to a gym with any regularity. At age 34, I am currently engaged in no physical activities whatsoever, and the Nintendo Wii does not count.

If I intend to be an active grandparent someday, I need to start now, and the best way to do that, in the absence of any kind of free time which I might use to actually excercise at a gym or bike or run, is to start some kind of home routine. The obvious and simplest thing to start is with pushups and situps. So, let’s see if I can set a goal for myself, to do as many pushups as I can, three times a week, before bed. The Washington Post has a handy table to consult to assess your fitness level based on how many you can do by age.

(pause)

I just did 20 pushups. The last 3 were with the baby deciding to ride along, which accelerated my decline, but I doubt I’d have lasted much longer regardless. That felt like a lot, but 20 is only 3 more than Poor and 4 less than Fair. I need to reach 30 to hit Good. Ten more! I’ve got a way to go I guess. I am loath to be too ambitious because then I’ll fail. I need to keep my goals modest so that the sense of progress keeps me motivated.

20 pushups is indeed Good… if I was 50-59 years old 😛