Carbs are NOT the enemy.
Limiting carbs is officially trendy. From the low fat / no fat movement of the 80’s and 90’s (which was also dangerous and ridiculous) we have officially put the thing down flipped it and reversed it to be ‘carbs make you fat’. With so much conflicting information out there about carbohydrates, fat storage, and our metabolisms, it's no wonder you have a fear of carbs.
It has become a pretty regular occurrence for a new client to tell me: “I don’t digest carbs”.
That’s a weird sentence. Do you mean…. all carbs? Like you don’t digest rice, or honey, or fruit, or potatoes. Or do you mean you don’t digest pasta and bread? There is a massive difference.
Let’s not complicate this conversation with people who have maldigestion of vegetable fibres, SIBO, or gluten intolerance etc for just a moment.
Our bodies are designed to use carbohydrates as a fuel source. Our biochemistry is literally designed that way. We turn the carbohydrates from our food into glucose in our cells and in our muscles and then we use it up. Yes, sure, when we don't have enough in the body we then go looking for fats (and muscle) to use as fuel but that is much MUCH more difficult for our body to do. And no, we don't end up burning our fat stores most of the time... we can end up burning our lean muscle mass. If we have carbohydrates handy they are the preferred source of fuel for our bodies (1).
When you don't eat enough carbohydrates then it can affect certain hormonal functions in the body including the thyroid, our progesterone, oestrogen, testosterone and cortisol production. They are all made from the same building blocks -- carbohydrates.
Female hormones in particular are extremely sensitive to our diet. This means that not providing your body with an adequate amount of calories or carbohydrates can cause significant disruptions to the production of the key female hormones, such as luteinizing hormone (LH), follicle-stimulating hormone (FSH), oestrogen, progesterone and testosterone. These hormones are vital for efficient reproductive processes.
A number of these female hormones are made in the hypothalamus and pituitary glands in the brain. These glands work in combination with the adrenal gland to form the hypothalamic-pituitary-adrenal (HPA) axis, which regulates functions like: mood, digestion, stress response, immunity, libido, metabolism and energy levels. All components of the HPA axis are very sensitive to factors like stress and not having enough energy available in the body. Thus, failing to consume either enough calories or carbohydrates can have a knock-on effect, negatively impacting female fertility, which may lead to issues such as hypothalamic amenorrhea (absence of a natural period) or irregular periods (2).
On top of this, hormone imbalances caused by lack of energy, which can occur on a low-carbohydrate diet, can also lead to loss of bone density, increased inflammation, worsened heart health, lack of energy, disrupted sleep, low moods and an increased chance of fat storage (particularly around the abdomen).
To add fuel to the fire, not eating enough carbohydrates has been linked with higher cortisol levels (stress hormone), which can further reduce the function of the pituitary gland and make the problem worse (3).
Low carbohydrate or calorie consumption has also been shown to suppress your levels of leptin. Leptin is a hormone released by the fat cells and helps the body maintain its weight by inhibiting hunger and regulating energy balance. For this reason, it is sometimes referred to as the ‘satiety’ or ‘fullness’ hormone. Aside from the obvious consequences of low leptin levels, such as increased hunger, it can also lead to amenorrhea.
And guys the news is just as bad for you: Scientists found a high-carb diet generated higher levels of testosterone and lower levels of cortisol than a low-carb diet over just 10 days. And when combined with intense exercise, low-carb diets actually increased stress hormones and lowered T levels (4).
Finally, low-carbohydrate diets can affect the function of your thyroid hormones, which are important for a whole range of bodily functions from heart rate, to cholesterol, to your menstrual cycle. The thyroid gland produces two hormones: thyroxine (T4) and triiodothyronine (T3), and as with the other hormones mentioned, these are also very sensitive to carbohydrate and calorie consumption. Low intakes of carbohydrates can reduce the levels of T3 in the body. One study found that serum T3 levels decreased rapidly in women following a low carbohydrate very-low-caloric diet, however this fall in T3 can easily be reversed simply by consuming more carbohydrates. Negative consequences of low T3 levels can include lack of concentration, low mood and weight gain (5,6)
Now, in saying all of that, it is the TYPE of carbohydrates that change the whole game.
If you eat candy, pastries and some refined flour pasta full of gluten, GMO wheat etc, it is entirely different to eating, let's say, a roasted sweet potato. Especially when you have gut issues or food sensitivities. That whole sweet potato is full of vitamins and minerals and fibre that do wonders for your health and hormone regulation. It is about QUALITY carbohydrates rather than quantity in most cases.
I also recommend having some sort of protein and fat alongside your carbohydrates to slow down the insulin response on your blood glucose.
BUT YOU STILL NEED CARBOHYDRATES.
If you have been avoiding carbs for a while, start slowly, increase your intake bit by bit with carbohydrates you can tolerate well, and remember there is no race to the finish line here. There is no finish line. There is only your long term health to consider.