Sceptically Fit

23/10/2011

Cycling fast preserves glycogen and burns fat.

Filed under: Exercise — Sceptically Me @ 00:45

A new study has found that cycling by pedalling fast is more efficient than cycling at a slower cadence but greater force (ie a higher gear). Oxygen consumption, heart and breathing rates and blood lactate levels were very similar between both sets of cyclists. The key difference was that cyclists pedalling at the faster rate had a higher utilisation of fat.

The greater glycogen depletion at 50 rpm occurred only in fast-twitch muscle cells. Slow-twitch muscle cells lost comparable amounts of their glycogen at 50 and 100 rpm, but fast-twitch cells lost almost 50 percent of their glycogen at 50 rpm and only 33 percent at 100 rpm, even though the exercise bouts lasted for 30 minutes in each case.

This rapid loss of carbohydrate in the fast-twitch cells during slow, high-force pedaling probably explains why slow pedaling is less efficient than faster cadences of 80-85 rpm.

Basically, as the fast fibers quickly deplete their glycogen during slow, high-strength pedaling, their contractions become less forceful, so more muscle cells must be activated to maintain a particular speed. This activation of a larger number of muscle cells then leads to higher oxygen consumption rates and reduced economy.

This scenario, in which slow pedaling pulls the glycogen out of fast-twitch muscle cells, may sound paradoxical but it isn’t; after all, slow pedaling rates are linked with high gears and elevated muscle forces, while fast cadences are associated with low gears and easy muscle contractions.

Since fast-twitch fibers are more powerful than slow-twitch cells, the fast-twitch fibers swing into action at slow cadences, when high muscular forces are needed to move the bicycle along rapidly.

On the other hand, “fast” pedaling rates of 80-100 rpm are not too hot for the slow-twitch cells to handle. Slow-twitch cells can contract 80-100 times per minute and can easily cope with the forces required to pedal in low gear.

Another possible paradox in the Wisconsin/Wyoming research was that fast pedaling led to greater fat oxidation, even though maximal fat burning is usually linked with slow-paced efforts.

Basically, the higher fat degradation at 100 rpm occurred because the slow-twitch cells handled the fast-paced, low-force contractions. Slow-twitch fibers are much better fat-burners than their fast-twitch neighbors.

 

22/10/2011

Carbohydrates not Saturated fat biggest risk factor for Cardiovascular Disease

Filed under: Health and Nutrition — Tags: , , , , — Sceptically Me @ 23:54

Another study just published that showing the link between high glycemic  foods and heart disease, not saturated fat.

Abstract

The dietary intake of saturated fatty acids (SAFA) is associated with a modest increase in serum total cholesterol, but not with cardiovascular disease (CVD). Replacing dietary SAFA with carbohydrates (CHO), notably those with a high glycaemic index, is associated with an increase in CVD risk in observational cohorts, while replacing SAFA with polyunsaturated fatty acids (PUFA) is associated with reduced CVD risk. However, replacing a combination of SAFA and trans-fatty acids with n-6 PUFA (notably linoleic acid) in controlled trials showed no indication of benefit and a signal toward increased coronary heart disease risk, suggesting that n-3 PUFA may be responsible for the protective association between total PUFA and CVD. High CHO intakes stimulate hepatic SAFA synthesis and conservation of dietary SAFA . Hepatic de novo lipogenesis from CHO is also stimulated during eucaloric dietary substitution of SAFA by CHO with high glycaemic index in normo-insulinaemic subjects and during hypocaloric high-CHO÷low-fat diets in subjects with the metabolic syndrome. The accumulation of SAFA stimulates chronic systemic low-grade inflammation through its mimicking of bacterial lipopolysaccharides and÷or the induction of other pro-inflammatory stimuli. The resulting systemic low-grade inflammation promotes insulin resistance, reallocation of energy-rich substrates and atherogenic dyslipidaemia that concertedly give rise to increased CVD risk. We conclude that avoidance of SAFA accumulation by reducing the intake of CHO with high glycaemic index is more effective in the prevention of CVD than reducing SAFA intake per se.

Taking Time Out

Filed under: Health and Nutrition — Tags: , , — Sceptically Me @ 12:15

More evidence that meditation has a real tangible benefit. I’ve been contemplating bringing meditation into my routine for a while now, but with the usual procrastinating type excuses I have yet to find time. This is one more reason to try to.

Both before and after the 5 week period, everyone took part in a brief 15 minutes of attempted focused attention meditation. They were told: “relax with your eyes closed, and focus on the flow of your breath at the tip of your nose; if a random thought arises, acknowledge the thought and then simply let it go by gently bringing your attention back to the flow of your breath.” While they meditated, people wore a cap full of electrodes, creating a picture of their brain activity.

Billions of neurons in the human brain communicate by generating small electro-chemical signals. When probes from an instrument that measures electrical energy are placed near a brain cell, a voltage change can be registered whenever the neuron is active. These electrical potentials are relatively small and cannot be monitored individually in humans without actually opening the head – at least not yet. But, because neighboring neurons frequently are active close together in time, the behavior of a group of neurons can be measured with electrodes placed on the scalp.

People in the meditation group could attend up to nine, 30-minute meditation instruction sessions across a five week period. In actuality, they attended a little under 7 instruction sessions, averaging 5 hours and 16 minutes of training in total.

Even with this small amount of practice, the researchers found big differences in brain functioning. Specifically, meditation training seemed to shift activity in the frontal regions of the brain towards a pattern indicative of greater positive, approach-oriented emotional states.

The Five Flavours of Paleo

Filed under: Health and Nutrition — Tags: , , — Sceptically Me @ 10:11

Dan’s Plan summarises the five major Paleo diet theories: Loren Cordain – The Paleo Diet; Robb Wolf – The Paleo Solution; Art De Vany – The New Evolution Diet; Mark Sisson – the Primal Blueprint; and Paul Jaminet and Shou-Ching Jaminet – Perfect Health Diet.

So, at the end of the day what are we left with? Well, it seems like there is a clear consensus that non-starchy vegetables are a critical part of a good diet and should be consumed freely and regularly. Meat and fish are also unanimously recommended, although there is some difference of opinion with regard to which particular meats and fish to approach or avoid. Bear in mind that when thinking about meat and fish, we can think about: 1) how much fat and protein they contain; 2) saturated vs. poly- vs. mono-unsaturated fats; and 3) ratios of omega-6 to omega-3 fats. We feel that there is sound science to support the decision to seek out sources of meat and fish that are high in omega-3 fats (salmon) and low in omega-6 fats (grass-fed beef and lamb). Among the paleo advocates listed here (perhaps not surprisingly), there is also consensus regarding most of the foods that one should avoid. A paleo diet clearly excludes grains, legumes, processed foods, and sugars.

Then there are the gray areas in which the opinions and the science are not as clear or consistent. These areas include dairy, fruits and berries, nuts, and starchy vegetables. Let’s walk through each of these one at a time. For dairy, the primary offending components appear to be milk sugars (e.g., lactose), proteins (e.g., casein), and hormones or growth factors. This is why those who are more lenient toward dairy tend to allow cream, (clarified) butter, and fermented dairy (yogurt, kefir, some cheeses) into the diet. These products typically have little to no milk sugars left because they have been excluded from the final product (cream) or have been chewed up by bacteria (yogurt). It is also important to bear in mind that dairy products from animals raised on grass will contain more favorable omega-6 to omega-3 ratios of fats than will dairy products from animals raised on grain. Fruits and berries are great for satisfying a paleo sweet tooth, but we have to careful about the types and amounts that we consume. Aim for fewer servings of fruits and berries if you are looking to lose weight and always aim for fruits and berries that have higher levels of nutrients and lower levels of fructose. Nuts are great sources of high density energy and they are portable and convenient. Like fruits and berries, people who are looking to lose weight should limit their consumption of nuts and, like meat and fish, all people should try to eat nuts that have higher levels of omega-3 fats and lower levels of omega-6 fats (e.g., macadamia nuts). Starchy vegetables are a good source of nutrients and carbohydrates for active people. Again, these foods should be consumed with some moderation and we like to scale up or down our consumption of starchy vegetables on the basis of our activity levels throughout the week – high levels of activity permit greater consumption of starchy vegetables, whereas we tend to avoid them more when activity levels are not quite so high.

Would you like some chips with your salt?

Filed under: Health and Nutrition — Tags: , , — Sceptically Me @ 08:06

Or why I refuse to cut back on salt.

A study from Belgium has found an association with  decreasing salt consumption and cardiovascular death.

Jan Staessen, a professor of medicine at the University of Leuven in Belgium and one of the authors of the study in Wednesday’s Journal of the American Medical Association, says this study does not support the recommendation of a general reduction of salt intake for everyone, although salt reduction could be beneficial in lowering the blood pressure of people with hypertension. “Lower sodium intake is recommended for people with high blood pressure and people with heart failure, but recommending it to the population as a whole, I wouldn’t do without proving it’s completely safe,” he says.

“If one lowers sodium intake to lower blood pressure, this change in sodium activates several systems (including the renin-angiotensin aldosterone system) that conserve sodium, and those systems are implicated in disease processes such as damaging the arterial wall and kidneys,” Staessen says,

 

via The Great Fitness Experiment

21/10/2011

Is there a case for eating phytates?

Filed under: Health and Nutrition — Tags: , , — Sceptically Me @ 23:42

Don from Primal Wisdom discusses some of the effects of phytates on the body including potentially cancer prevention.

 

According to researchers from Linus Pauling Institute of Science and Medicine, phytates appear to have anticancer effects by binding excess minerals in tissues, depriving tumors of essential minerals.[4 pdf]

Vucenik and Shamsuddin discuss the anticancer properties of phytate in detail; all information and quotes remaining in this post come from their report in the Journal of Nutrition.[5 full text]

Almost all mammalian cells contain phytate in the inositol hexaphosphate (IP6) form and others with smaller numbers of phosphate groups (IP1-5).  When we ingest dietary phytate, intracellular levels of IP6 increase, and from this cells increase the levels of the other forms, which appear involved in “cellular signal transduction, regulation of cell function, growth, and differentiation.”

Dietary phytate enters the blood stream and reaches tissues, including tumors, far from the gut.

Tumor cells take up phytate, probably by pinocytosis or receptor-mediated endocytosis.

Phytate inhibits malignant growth in human leukemic, colon cancer, breast cancer, cervical cancer, prostate cancer, and liver cancer cells.

High Intensity Intervals the key to Health

Filed under: Exercise — Tags: , , — Sceptically Me @ 10:54

A new study published shows the benefits of high-intensity intervals for increasing cardiovascular fitness over other forms of exercise.

The study shows that by increasing the intensity of your exercise, you can beat back the risk of metabolic syndrome, the troublesome set of risk factors that can predispose people to type 2 diabetes, stroke and cardiovascular problems.

When the Jebsen Center researchers looked at the importance of the intensity of exercise versus the duration, intensity was far more important than duration in determining peak oxygen uptake.

They have also looked at the benefits of high intensity exercise in the form of interval training — where four or more short periods (typically 4 minutes) of very high intensity exercise are followed by a similar number of short periods of lower intensity exercise. This approach, called 4×4 interval training, is a quick way to increase your overall fitness, research from the Jebsen Center has confirmed.

 

Via Conditioning Research

09/10/2011

Organic is better – more evidence

Filed under: Health and Nutrition — Tags: , , , — Sceptically Me @ 10:04

A 30 year study has just been published comparing organic farming with conventional farming and have shown that organic farming is better and more feasible than the toxic unsustainable multi-national powered way.

In fact, studies like the Rodale trials (www.rodaleinstitute.org/ fst30years) show that after a three-year transition period, organic yields equalled conventional yields. What is more, the study showed organic crops were more resilient. Organic corn yields were 31 per cent higher than conventional in years of drought.

These drought yields are remarkable when compared to genetically modified (GM) “drought tolerant” varieties, which showed increases of only 6.7 per cent to 13.3 per cent over conventional (non-drought resistant) varieties.

The key points were

Importantly, the Rodale study, which started in 1981, found organic farming is more sustainable than conventional systems. They found, for example, that:

. Organic systems used 45 per cent less energy than conventional.

. Production efficiency was 28 per cent higher in the organic systems, with the conventional no-till system being the least efficient in terms of energy usage.

. Soil health in the organic systems has increased over time while the conventional systems remain essentially unchanged. One measure of soil health is the amount of carbon contained in the soil. Carbon performs many crucial functions: acting as a reservoir of plant nutrients, binding soil particles together, maintaining soil temperature, providing a food source for microbes, binding heavy metals and pesticides, and influencing water holding capacity and aeration. The trials compared different types of organic and conventional systems; carbon increase was highest in the organic manure system, followed by the organic legume system. The conventional system has shown a loss in carbon in recent years.

. Organic fields increased groundwater recharge and reduced run-off. Water volumes percolating through the soil were 15-20 per cent higher in the organic systems. Rather than running off the surface and taking soil with it, rainwater recharged groundwater reserves in the organic systems, with minimal erosion.

Organic farming also helps sustain rural communities by creating more jobs; a UN study shows organic farms create 30 per cent more jobs per hectare than nonorganic. More of the money in organic farming goes to paying local people, rather than to farm inputs.

Story from Real Food University

 

04/10/2011

Misguided Attempts to Help

Filed under: Health and Nutrition — Tags: , , , , , — Sceptically Me @ 17:50

Unhealthy food needs to be taxed more – but it needs to actually taking unhealthy food, not good basics like butter, full-fat milk, cream and especially not meat! Target processed food, target sugary and starchy foods! And of course, ban trans-fat! That’s one thing the Danes got right.

The government will consider introducing a “fat tax” to tackle Britain’s growing obesity levels, the prime minister, David Cameron, has said.

Cameron said drastic action was needed to prevent health costs soaring and life expectancy falling.

Under measures introduced in Denmark recently, a surcharge is being placed on foods that contain more than 2.3% saturated fat. The levy targets high-fat products such as butter, milk, cheese, pizza, meat, oil and processed food.

Falling Seriously Behind…

Filed under: Personal — Tags: , — Sceptically Me @ 17:41

Oh how I fell off the wagon.

My parents were due to be having a big holiday in my part of the world – visiting me several times overt the two and a half month period. Of course I’d be taking the time off when they were in town, but the only extended period was to be  the last ten days when a week of that time would be spent on a driving holiday.

Unfortunately my poor mother fell very ill in the first week and had to be hospitalised when she didn’t respond to treatment. And of course she doesn’t get that ill in the city that I live in. No, that happens in another country – it would be too easy to be able to just visit from home. No I spent the week in a little (nice) hotel on the outskirts of Dublin until Mum was well enough to fly to my city.

That first week, I managed to cope reasonably well health-wise. I went a little too short on sleep but I did manage to go for a run before breakfast most days (gentle 8km runs, and sprint intervals). The classic full breakfast meant I could fill up on eggs, bacon, mushrooms (and just a little bit of black pudding), and go through till dinner where I managed to make pretty reasonable choices (except for beers with Dad but that was on compassionate ground so ok!).

When I got home, Mum and Dad stayed in an apartment nearby. Which meant I was heading there after work. While I could keep my food choices pretty healthy I was already starting to notice the lack of exercise. I can’t face going for a run before work and actually being able to function and my gym doesn’t open early enough to go before work either. So I’m now looking at almost a month of not lifting heavy things. I actually feel weaker and like muscle imbalances are slipping back in. At least I was cycling to and from work.

Now we’re on the road – no time for any runs (and its pouring most of the time), no gym, barely any walking. And I’m making terrible food choices. I’ve eaten more wheat in the last five days then I’ve eaten in the last two months (and feeling the bloated sluggish effects). Unfortunately, now that Mum has her appetite back, filling up on breakfast isn’t working (although a lot of the hotels are a bit stingy with their eggs and bacon anyway…) as we stop for lunch and/or afternoon tea. And I’m weak. Weak enough that I ate the shortbread that came with the coffee I ordered.

Now, I do agree with the 80/20 rule, and I do agree that some things are exceptional moments that one should enjoy. So I don’t mind breaking my attempt at healthy eating if a)its really necessary (but how often is that really true?) or more likely b)its something I want to do. So I don’t mind that I’ve drunk more than a sensible amount of wine, beer and spirits over the last month. Nor do I begrudge the delicious sticky toffee pudding that I had for dessert on that first night. But I do begrudge eating not-good-quality bread products to pad out my meal. So trying to skip the sandwiches and find some kind of salad alternative. And I’ve now accepted that the sausages being served with breakfast are clearly far from the 98% meat products I’d buy for myself so they will remain on the plate.

Still a few more days to go, and I don’t plan to make an issue of it for the rest of the holiday. I will attempt to eat better and make sure its worth it when I don’t – today the place we stopped for coffee and cake was awful. The cake tasted at least two days old, and was clearly bought from a supermarket commercial bakery – two mouthfuls and I decided that bad cake isn’t worth it.

Due to Mum’s convalescence I don’t see my getting more exercise for a while, but I am going to try eat better when the options are there, and skip the bad options when they are only a snack.

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