Ben Greenfield on the 4 Dangers of aLow-Carb, High-Fat Diet

Ben Greenfield is author of the new book “Beyond Training”, in which you learn how to be healthy on the outside and inside, how to interpret your own biomarkers, and how to achieve amazing feats of physical performance without destroying your body or mind.Share5

Credit: Flickr Commons, Adam Wyles

I personally have experimented with very low carbohydrate diets combined with extreme amounts of exercise and have certainly noticed issues on my biomarkers of which I would have never been aware if I weren’t testing and tracking – and these were serious issues that threatened my long term hormonal health and longevity.

With low-carb, high-fat diets becoming more mainstream for everything from weight loss to physical performance, it’s very important for you to be aware of common pitfalls with this diet – particularly pitfalls that may be directly quantified in your own blood biomarkers. Here are four dangers of a low-carb, high-fat diet that you need to be aware of:

1. Triglycerides

Not only are high levels of circulating triglycerides a good way to get fat fast, but studies have consistently linked high triglyceride levels with heart disease, heart attacks and stroke. Fructose is one quick way to elevate triglycerides, but this really doesn’t seem to be an issue with high-fat, low-carbers. However, vegetable oils and animal fats can also raise triglycerides. The big issue here is that if these oils and fats have been exposed to high amounts of temperature and processing, triglycerides are getting dumped into your body chock full of free radicals. So if your high-fat diet includes a high amount of roasted seeds or roasted nuts, nut butters, heated oils such as heated coconut oil or heated extra virgin olive oil, barbecued meats or meats cooked at very high temperatures, then your triglyceride count is going to go up. You should have triglycerides that are less than 150mg/dL, and a triglyceride to HDL ratio that is no more than 4:1, but in most of the healthiest people I’ve worked with, triglycerides are under 100 and the triglyceride to HDL ratio is less than 2:1.

2. Inflammation

If you have high levels of cholesterol (which you probably do if you’re eating a high-fat, low-carb diet, then you need to be worried if your HS-CRP levels (a primary marker of inflammation) are above 1.0 mg/dL – even if you’re a hard charging athlete. I like to see most people under 0.5 for CRP levels, and here’s why: a high amount of inflammation in your body is going to make the cholesterol circulating in your bloodstream more likely to become oxidized, generating a high amount of heart and connective tissue-damaging free radicals. As a matter of fact, it’s more dangerous to have high levels of cholesterol and high levels of CRP than low levels of cholesterol and high levels of CRP – even if your high levels of cholesterol are “healthy”, big fluffy LDL particles, and not small, dense vLDL particles. In other words, no matter how many healthy fats you’re eating, these fats may actually come back to bite you if you’re creating high inflammation from too much exercise, not enough sleep, exposure to toxins and pollutants, or a high-stress lifestyle.

3. Glucose/HBA1C

Free-ranging glucose molecules in your bloodstream can adhere to cholesterol particles and cause those particles to remain in the bloodstream for long periods of time, since your liver can’t properly process cholesterol when it has a glucose molecule attached to it. The longer cholesterol circulates in your bloodstream, the higher the likelihood that it will dig its way into an endothelial wall and potentially contribute to atherosclerosis or plaque formation. This is why it’s so dangerous to eat a high-fat diet, but to also have your nightly dark chocolate bar, overdo it on the red wine, or have weekly “cheat days” with pizza, pasta, or sugar-laden ice cream. If you’re going to eat a high fat diet, then you need to ensure your fasted blood glucose levels are staying at around 70-90mg/dL, and your hemoglobin A1C (a 3 month “snapshot” of your glucose) is staying below 5.5. If not, your high fat diet could actually be significantly hurting you.

4. Thyroid-stimulating hormone (TSH)

Carbohydrates are necessary for the conversion of inactive thyroid hormone to active thyroid hormone, and if you’re on an extremely strict low carbohydrate diet, then you may actually be limiting this conversion. Your TSH is what tells your thyroid gland to “release more hormone,” so your TSH rises when your thyroid gland is underactive, or conversion of inactive to active thyroid hormone is inadequate. A high TSH means that the pituitary gland is releasing its hormone to try to get the thyroid to respond and produce more thyroid hormone. Because of inadequate carbohydrates, TSH will often elevate in a high-fat, low-carber – indicating potential for long-term thyroid and metabolic damage. If I see a TSH above 2.0 or a trend towards higher values in someone who is testing repeatedly, I get worried – and prefer to see TSH at 0.5-2.0. Of course, this doesn’t mean that you begin toshove carbohydrates indiscriminately down the hatch. However, it means that your high-fat, low-carb diet should include thyroid supporting foods rich in iodine and selenium, such as sea vegetables and brazil nuts, and should also include carbohydrates timed properly, such as before, during or after workouts, when the carbohydrate is more likely to be utilized for energy and less likely to spike blood glucose levels.

1 Reply

  • Hello

    Well not sure what to say ....I can see your post is helpful but at the same time because the community has so many Health Anxiety sufferers myself included I have to admit I skipped a lot because I try & avoid to many facts like I avoid Google as if I read to much I will swear I am in the negative categories you speak about and that just triggers my anxiety of ...but yes very interesting post x

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