Q. I read recently that the consumption of caffeine prior to exercise will assist the body in using body fat as fuel, up from 21% to 40%. The remaining fuel comes from stored carbs. Any truth to the story?
A. There may be a grain of truth to the story but not much more. Taking caffeine before exercise has been shown to increase energy expenditure (the number of calories burned) during exercise by around 10%. So if you would normally burn 200 calories in a half-hour, some extra caffeine might help you burn 220. Caffeine may also delay exercise fatigue and otherwise boost performance a bit. I didn’t find any evidence, however, that it increases the amount of fat used as fuel. Generally, the body taps into fat stores when available carbs have been depleted.
But here’s a little-known benefit of combining exercise with caffeine: Researchers have found that drinking caffeine and exercising regularly may decrease your risk of skin cancer (at least if you’re a mouse)!
Related Content: Benefits and Dangers of Caffeine
the key is really what you mix the caffeine with. Yohembie and caffeine for example will increase your ability to burn fat for fuel during exercise. Especially when taken first thing in the morning on an empty stomach.
I know that a handful of research studies have shown no change in substrate utilization, but what about stuff like this bel0w?
http://www.ajcn.org/content/33/5/989.abstract
http://journals.lww.com/acsm-msse/Abstract/1978/10030/Effects_of_caffeine_ingestion_on_metabolism_and.3.aspx
http://www.springerlink.com/content/d631q1467836rt32/
http://journals.lww.com/acsm-msse/abstract/1987/04000/a_high_carbohydrate_diet_negates_the_metabolic.6.aspx
Ben,
In your Get-Fit-Guy Newsletter today, you mentioned that caffeine help some exercise “up to” 10 times longer. Is that right? I know everyone would be different, but 10 times longer seems pretty significant? Forgive me if I misquoted this statistic. Thanks!
Does it really matter if you are burning fat or burning carbs? In the end, at least when it comes to weight loss, it’s the amount of calories you burn that counts, not where they come from.
It seems like I learned in a cell biology class that caffeine causes cells to release fat. Don’t remember the mechanism though.
During exercise it takes a little while for fat metabolism to get going but you do not need to burn through your carbs before you burn fat. Sorry but that is just not correct.