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Is caffeine making me fat?

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So I have read the Whole30 book, and am now reading through the It Starts With Food, and I came across a part in chapter 5 that suggested that caffeine can increase cortisol levels, especially when consumed in the later part of the day when cortisol levels should be down.  I wanted to know if there was scientific evidence for this?  Is it true that caffeine increases cortisol levels?


I'm concerned that by drinking black and green tea consistently through the day may be keep my cortisol levels too high, causing that belly fat we all know is a big health risk.  I'm on day 25 of the Whole30 and I feel really good and I'm probably going to do a Whole60, but I worry because most of my body fat is belly fat, which is associated with high cortisol levels and can be a predictor of more serious health problems.  I’m within the normal BMI range (which I know isn’t the best weight gauge) and I’ve actually lost 4lbs during this process, but I worry about the excess belly fat and more importantly, the health concerns associated with it.  

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It Starts With Food has a whole appendix with sources for each chapter, you might start by checking there.


You could also just switch to plain water, caffeine free herbal teas, and infused water (just slice whatever fruits or vegetables sound good into a pitcher, add fresh herbs if you want, fill with water, and let sit overnight in the fridge -- I like sliced cucumber and slices of either lemon or lime as a refreshing treat in the summer) and see if you notice a difference. 

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Ok so that morning coffee ladies...... Consider that in the morning your cortisol levels are at their highest having fasted overnight. Then consider that raised cortisol levels can prevent weight loss (& even encourage weight gain...). Then consider that coffee raises cortisol levels. Consider also that stress (read that as stress, exercise, fatigue, illness, inflammation etc etc etc) ALSO raises cortisol levels.

Then consider that the older you get the longer it takes for your cortisol levels to drop - so in a 21yr old their cortisol levels will return to normal within a matter of hours. In a 70yr old, however, it can day several days for cortisol levels to return to normal.

So think about a 45yr old wakening in the morning, cortisol levels are at their peak, she trains hard raising them further, then reaches for the coffee mug raising them further still......

We are each of us somewhere in the midst of  that 21-70 year age bracket which means that our cortisol levels our having a fairly big impact on our weight.

Still want that morning cuppa....?










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My post above shared by Meadowlily was one I'd made in a support thread to explain, in layman's terms the effect that coffee can have on cortisol levels, which can in turn prevent weightloss, or encourage weight gain. It is , of course, dependant on whether or not your cortisol levels are abnormally high, or are prone to being high due to external stressors like stress itself, insomnia, exercise, illness etc. The older you are, the longer it takes for your cortisol levels to return to normal once raised.

It should be noted that many of the research articles that I have read indicate that it is the coffee bean itself that raises the cortisol, and not the caffeine, and therefore switching to decaf may be of no benefit.

With all of that said it is worth noting that caffeine does in fact have a mild thermogenic effect, increasing the metabolic rate by a very small percentage (3-4%)

Green tea extract does something similar in that it acts in two ways to boost noreponephrine levels & inhibit the degarding of cyclic AMP (Adenosine Monophosphate) and therefore may increase energy expenditure and fat oxidation, with a thermogenic effect greater than that of the same amount of caffeine. Studies suggest that a caffeinated green tea extract could help decrease body mass index, body weight & waist circumference - although this may not amount to a significant loss over time. Decaffeinated green tea extract does not produce the same result.

Green tea extract can however cause acute liver toxicity with sustained use. Caffeinated green tea on the other hand is safe to drink and has many other health benefits.

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