I came across a study called Low Calorie Dieting Increases Cortisol by Yomiyama and colleagues 2010 in the journal of the American Psychosomatic Society.
The study was looking at dieting and the effect is has on psychological and physical stress so not immediately related to Hashimoto’s but if you are struggling with your weight at all because of hypothyroidism and you are restricting calories in hopes of losing weight, this is why this study is important.
Aside from that, most of us have been on a diet at one point in time. My mind is way too obsessive to make long term caloric restriction work for me so I never dieted much. I tried once before a friends wedding to fit in to a bridesmaid dress. Other than that if I tell myself not to eat something, that is all I think about. I did do well when I did AIP but my body didn’t really give me much of a choice and I probably felt my best physically and mentally when I was eating as clean as that diet calls for.
The hypothesis of this study is that diets fail because they increase stress and stress can increase weight through the HPA axis which also affects energy metabolism.
They were looking to measure cortisol in dieters and also noted that it has been documented that dieting produces negative emotions like depression, anxiety, low self esteem, nervousness and irritability.
This study was only 3 weeks long so it isn’t a great representation of how much a diet would effect cortisol long term and whether that long term stress would impede weight loss or even cause weight gain. The participants were either monitoring their diet or not OR restricting their diet or not.
Salivary cortisol was measured at the beginning for a baseline measurement and then at the end of the 3 week study. Each time they were measured for two days and 3x each day. First thing in the morning, 45 minutes after waking and 12 hours after waking.
Questionnaires were given asking about potential activities that would affect cortisol such as exercise, caffeine, alcohol, pain, stressful events etc.
Participants in the diet restriction group were told to follow a diet of 1200 calories a day with 50% of that coming from carbs, 30% from fat and 20% from protein. They also completed a food journal to be sure they monitored their intake.
Participants who were just monitoring their diet didn’t restrict calories and just used a food journal. The restricting food only (not monitoring) were given all of their food for the study. The control group didn’t do any of this and just ate their normal diet.
Part of what they were measuring was the cortisol awakening response which is the time between when you wake up and 30-45 minutes later. Psychological stress was also measured by questionnaire. Perceived stress was increased in those who monitored their caloric intake. Just restricting diet and not monitoring did not increase perceived stress but it did increase the amount of cortisol in the body in the evening but not in the morning (so no effect on the cortisol awakening response).
This info is important because one of the main jobs of cortisol is to increase energy via glucose which would also increase insulin. The authors do indicate that their study did not relate the release of cortisol to weight gain and they could not find studies on this in humans but there are mouse model studies showing a relationship between cortisol output and weight gain.
When cortisol is high, we know it increases the body’s own production of glucose as I said. It also decreases the body’s ability to use the glucose it makes or the glucose you take in through your diet which will in turn increase your blood sugar levels.
High cortisol breaks down protein and keeps your body from making it. This translates to high cortisol breaks down your muscle and can affect your immune system response to offenders or potentially to your antibodies against your thyroid.
High cortisol decreases the immune systems Th1 response and increases Th2 response- these need to be in balance. Having either one high causes inflammation in the body which further increases stress biochemically.
High cortisol also plays a role in bone and collagen loss as well as decreasing absorption of amino acids from the protein we eat.
Signs and symptoms of high cortisol include:
insomnia or poor sleep
brain fog, poor memory
depression, anxiety, irritability
high blood sugar, high insulin
craving for sugar
weight gain, especially around belly
fatigue
poor digestion and absorption due to your central nervous system being is sympathetic mode
night sweats
high blood pressure
poor immune system function
low sex hormones
bone loss or osteopenia/osteoporosis
easy bruising, poor wound healing
weakened muscles
You can test for cortisol via a salivary panel or a Dutch test but the research shows that a single day test is not accurate enough to make any conclusions about someone’s cortisol levels because our cortisol levels vary so much throughout the day. A serum cortisol test done in the morning may be a more cost effective way to see if you are dealing with high or low cortisol at least in the morning. It is more accurate than saliva but you don’t get the cortisol rhythm throughout the day.
Working with someone like myself to see where your body is at, what your diet is like, what your cells need is a great first step to improving your cortisol levels and the only time I have clients do caloric restriction is during a period where we are working on their body’s detoxification and even at that it isn’t for long.
That’s it for this episode. Thanks for listening. Download your free definitive guide to hashimoto’s on my website when you sign up for my newsletter. You can sign up for a free discovery call on my website too under the work with me tab. And if you want your free 3 day meal plan you can get that on the meal plans tab on my website as well. That is help for hashimoto’s dot com.
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