Posts Tagged ‘caffeine’

Nutrition Myth Busted: Caffeine and Dehydration

December 9th, 2009

coffee

For years & years, we have been told that caffeinated beverages (coffee, tea, etc) are diuretics and that they dehydrate us and that they do not count towards those magic 8 glasses of water we are all supposed to drink each and every day.

And for years & years, I thought this was a colossal line of B.S.

And I was right.

According to this study & that study, there is no valid scientific support for the suggestion that consumption of caffeine-containing beverages as part of a normal lifestyle leads to fluid loss in excess of the volume ingested or is associated with poor hydration status.

Therefore, there would appear to be no clear basis for refraining from caffeine containing drinks in situations where fluid balance might be compromised.

So, the next time someone tells you that you shouldn’t drink coffee because it will dry you up like a California Raisin, send them over to Health Habits for a little book learnin’.

And once again, like those guys on the Discovery Channel, I declare this nutrition myth…BUSTED

myth-busted

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Does Coffee Make You Fat?

July 28th, 2009

coffee

I just finished reading Why Diet and Exercise Fail…and I am ticked off.

starbucks IV addictTicked off because author Daniel Matthew Korn is making me re-think my morning cup of Gold Coast.

Korn believes that long term caffeine consumption, when combined with a typical Western Diet, is akin to throwing gas on your obesity bonfire.

Or, as Daniel says, “long term caffeine use, in combination with other dietary factors can contribute to lowering our ability to use our stored body-fat and interfere with our storage of nutrients”.

Why would coffee lead to obesity?

Theory #1

  • Long term caffeine use can lead to elevated stress hormones (ie Cortisol)
  • And heightened cortisol levels is associated with obesity

Theory #2

  • Chronically elevated cortisol levels results in increased feelings of hunger
  • And obviously hunger leads to eating and drinking more coffee and eating more food and…

Theory #3

  • Chronic caffeine use may interfere with your sleep patterns
  • And sleep deprivation is associated with obesity

Korn’s Conclusion

Chronic caffeine use contributes to obesity because:

  • it increases your level of stress hormones
  • which messes with your brain chemistry
  • and increases your hunger
  • causing you to eat more crappy processed foods
  • while you lay in bed tossing and turning because you can’t sleep

My Conclusion

As Korn mentions, there is very little research into the direct effect caffeine has on metabolism and obesity.

This leaves his theory open to attack.

I can hear the comments already – Association and/or Correlation is not Causation.

And they are right. Korn is making some assumptions.

And good for him. Out of these assumptions, researchers can design studies to test if caffeine has a direct effect upon obesity.

Until then, you can:

  1. Ignore his caffeine/obesity theory as unproven
  2. Or, test the theory on yourself. Sadly, that is the route I am taking…starting tomorrow.

Note: I will be reviewing the rest of Why Diet and Exercise Fail in an upcoming post.

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Exercise easier with a cuppa joe

April 2nd, 2009

coffee-you-can-sleep-when-youre-dead

For decades, endurance athletes have relied on caffeine as a performance aid.

They claimed that a pre-workout cup of coffee helped them to push themselves harder and for longer periods of time.

And along the way, science has backed up that belief:

  • In 1979, scientists found that caffeine helped cyclists improve their performance by 7% during a 2 hour workout.
  • In 1991, cyclists dosed with 9mg of caffeine per kg of bodyweight were able to increase their endurance by 51%
  • In 1995, cyclists performing high intensity circuits were able to improve their endurance by 29% with a dose of 5.5mg of caffeine per kg of body mass.

Pretty good, right?

The only problem is that no one really knew why caffeine improved athletic performance…until now.

Researcher (and cycling geek) Dr. Robert Motl has spent the last 7 years considering the relationship between physical activity and caffeine.

Today, he has a much better understanding of why that cuppa Joe he used to consume before distance training and competing enhanced his cycling ability.

Early in his research, he became aware that “caffeine works on the adenosine neuromodulatory system in the brain and spinal cord, and this system is heavily involved in nociception and pain processing.”

Since Motl knew caffeine blocks adenosine from working, he speculated that it could reduce pain.

A number of studies by Dr. Motl support that conclusion, including investigations considering such variables as exercise intensity, dose of caffeine, anxiety sensitivity and gender.

The good doctors latest study “looks at the effects of caffeine on muscle pain during high-intensity exercise as a function of habitual caffeine use,” he said. “No one has examined that before”.

And what did they find?

  • Caffeine reduces pain during exercise.

  • Less pain means you can work harder.

  • Less pain means you can work longer.

The Science

The study’s 25 participants were fit, college-aged males divided into two distinct groups:

  1. Subjects whose everyday caffeine consumption was extremely low to non-existent,
  2. And those with an average caffeine intake of about 400 milligrams a day, the equivalent of three to four cups of coffee.

After testing their baseline aerobic fitness, Dr. Motl tortured his subjects with two monitored high-intensity, 30-minute exercise sessions.

An hour prior to each session, cyclists – who had been instructed not to consume caffeine during the prior 24-hour period – were given a pill.

On one occasion, it contained a dose of caffeine measuring 5 milligrams per kilogram of body weight (equivalent to two to three cups of coffee); the other time, they received a placebo.

During both exercise periods, subjects’ perceptions of quadriceps muscle pain was recorded at regular intervals, along with data on oxygen consumption, heart rate and work rate.

The Results

Obviously the most important result was that caffeine reduced the pain of intense physical activity.

But Dr. Motl also found that when it came to the reduction of pain, “caffeine tolerance doesn’t matter”.

Caffeine-junkies and the herbal tea drinkers received the same pain reducing benefit from their little caffeine pill.

So, what now?

Dr. Motl wants to see what effect caffeine’s pain-reducing abilities has on sport performance.

“We’ve shown that caffeine reduces pain reliably, consistently during cycling, across different intensities, across different people, different characteristics.

But does that reduction in pain translate into an improvement in sport performance?”

Interesting question for sure, but I am way to impatient to wait for the next Dr. Motl study.

If you’re like me, check out this list of caffeine based beverages and let’s get physical.

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