How The Keto Diet Is Killing Your Metabolism


The ketogenic diet is a powerful new tool to hit the mainstream recently. This style of eating has substantial data behind it showing that it can boost fat-burning, reduce inflammation, boost cognitive performance, and more. What has not been covered quite enough are common keto side effects and how you can avoid them to make the best of this powerful eating style.

Although there can be many different side effects that manifest while becoming keto-adapted, they all stem from similar underlying issues. In this article, I outline what those underlying issues are, their related keto side effects, and simple strategies to overcome them so you can become keto-adapted as smoothly as possible.

Dizziness & Drowsiness 

When you are hypoglycemic while also not being fully keto-adapted, you essentially have an energy deficiency within the body.  This is a short term adaptation that can lead to a variety of keto side effects.

During this time, you will likely feel dizzy and drowsy due to a general lack of energy. You may feel especially dizzy upon standing due to blood pressure dysregulation and inappropriate cortisol response (HPA axis dysregulation which we’ll talk about shortly).

Reduced Strength & Physical Performance 

During keto-adaptation, your body is learning to utilize a completely new fuel source that it has not had to use before. The muscles (along with the brain) contain tons of mitochondria for energy production that must now learn to utilize ketones as an energy source.

During this time, you will likely feel a significant drop in strength and ability to exert physical energy as one of the short term keto side effects. Luckily, once you become adapted you should see drastic improvements in these areas that are even greater than when you were sugar-adapted!

Keto Flu 

This is perhaps one of the most well-known keto side effects. Keto flu is exactly what it sounds like, the onset of flu-like symptoms that arises shortly after beginning a ketogenic diet. This includes symptoms like fatigue, runny nose, nausea, and headache.

Keto flu is a classic manifestation of hypoglycemia that can be corrected with simple strategies that I will outline shortly.

Sugar Cravings 

Many people find that during the beginning stages of a ketogenic diet they experience intense food cravings. These food cravings are typically for high-sugar foods and tend to really challenge your willpower.

This is a classic hypoglycemia response as well. The brain in particular requires lots of energy for normal function. When it receives a signal that you are hypoglycemic, a panic response occurs because of an underlying perception that you are starving to death (even if consciously you know you’re not).

At this point your brain begins to tell you that, “YOU NEED IMMEDIATE ENERGY NOW OR YOU’RE GOING TO DIE”! This is when you have intense sugar cravings. Luckily, once you begin to produce ketones for energy this panic response calms down.


Like most things in life, there are some drawbacks to the keto diet. While there are many benefits to being in ketosis, there are some downsides it’s important for you to know about.

“Keto Flu”

Although the ketogenic diet is safe for healthy people, there may be some initial side effects while your body adapts and switches its gears from burning sugars to burning fats (i.e. ketones).

This is often referred to as “keto flu” – and is usually over within a few days.

Keto flu includes poor energy and mental function, increased hunger, insomnia, nausea, digestive discomfort and decreased exercise performance.

In order to minimize this, you can try a regular low-carb diet for the first few weeks. This may teach your body to burn more fat before you completely eliminate carbs.

A ketogenic diet can also change the water and mineral balance of your body, so adding extra salt to your meals or taking mineral supplements can help. For minerals, try taking 3,000–4,000 mg of sodium, 1,000 mg of potassium and 300 mg of magnesium per day to minimize side effects.

Muscle Mass Loss

While in ketosis, there is a greater risk of losing lean muscle mass tissue. Insulin is a highly anabolic hormone and is one of the primary reasons why those who are attempting to gain muscle often load their diets up with extra carbohydrates.

If you remove all the carbs on purpose, you lose this anabolic response.

It also becomes very hard to sustain an intense weight lifting program on little to no carbohydrates because your muscles aren’t getting the weight lifting stimulus to help retain lean muscle mass that they normally would.

Low Energy Levels

While some people function great in ketosis and could stay in this state forever, they are not the norm. Many people find they just don’t feel as good as they did when they were eating more carbs.

Some people feel downright miserable on a keto diet. These people are not the norm though but if you are one, that’s good indication that you should consider stepping away from this diet protocol.


The normal advice to help relieve constipation includes drinking enough water, increasing non-starchy, fibrous vegetable intake, and using sugar-free candy containing sugar alcohols as a mild laxative.

If you have tried these ideas and they haven’t worked for you, or if you have trouble with constipation no matter what kind of diet you eat, here is a study to show you that fiber is not necessarily the magic “cure-all” for constipation.

Most people believe that constipation is caused by a lack of fiber in the diet, but this may not be so because constipation is usually caused by something you ARE eating, not by something you’re NOT eating.

If you experience constipation on a ketogenic diet, it may not be because you are eating less fiber; it is probably because you have started eating something that you were not eating before (that is hard for you to digest).

In order to eat a ketogenic diet, which is a high-fat, limited protein, ultra-low-carb diet, most people find themselves turning to high amounts of foods that are notoriously difficult to digest, including nuts, low-starch vegetables such as crucifers, and full-fat dairy products.

Additionally, low carb foods like cucumbers, tomatoes, squashes, avocado, okra, and olives will aid in speedy digestion.

Personally, I find that most people who experience constipation on a ketogenic diet are those who are not drinking enough water.

Try to get at least 75 to 125 ounces of water daily when going keto… or following any diet for that matter.

Here’s an overview of the Pros and Cons of the ketogenic diet plan.


• Can lead to a greatly reduced appetite
• Allows you to eat plenty of fat rich foods, which you may enjoy
• Normally leads to a loss in body weight
• May help improve cholesterol and heart health problems
• Can lead to a reduction in blood pressure
• Stabilizes insulin and blood glucose levels


• May cause low energy levels
• Requires a two week adaptation period in which the ‘keto flu’ may be experienced (extreme tiredness, brain fog, and not feeling so well overall)
• May lead to constipation
• Can be easy to overeat in calories if you are not careful
• Is not ideal for athletes as intense exercise is limited
• Is rather challenging to follow as you will never just be able to ‘eat’ – you’ll always need to plan out the macros of your meals.


Ketogenic Diet and Thyroid

There is an idea in the functional medicine community that following a ketogenic diet is bad for thyroid health. This idea is not supported by research. There is some evidence that following a ketogenic diet may lower T3 levels however. This does not necessarily qualify as hypothyroid and may actually be beneficial.

In fact, this lowered T3 is seen with calorie restriction and protein restriction as well. Evidence seems to point to lowered T3 as a physiological adaptation in the body that allows for a deeper state of ketosis and preserved muscle mass (this is a good thing).

This is given that TSH and T4 levels remain normal.

This is where it is really important to monitor how you are feeling on a day-to-day basis and determine how you are responding to a ketogenic diet. T3 levels may be slightly depressed, however if you are feeling very good then it is not really a concern.

Like I said this drop in T3 allows for deeper ketosis and preserved muscle mass. Additionally, and interestingly enough, low T3 levels are actually associated with a longer lifespan in research.

Follow A Health Focused Program

Instead of trying to lose weight, it’s time to start getting healthy.

Sure, in most of my programs I claim they can help you lose a lot of weight in a short period of time, BUT the difference between my programs and other “lose-weight quick” programs is mine are “health-focused.”

That means:

  • They are based on real food, quality over quantity, and minimum supplements
  • They help you balance your hormones
  • They optimize your fat-burning metabolism, so it works for you instead of against you

If you’re ready to finally start a health-focused program that delivers real and FAST results. Results that you can actually keep off, then I invite you start with my 8-Week Metabolism Makeover.

Why You Shouldn’t Do Keto For Too Long

After the ketogenic reset, your body has regained metabolic health and can now switch between burning fats and sugars.

Because there are certain tissues in the body that can only burn sugar for energy, this is when I recommend implementing a periodic ketogenic diet.

This means that once or twice a week, you have a meal that has higher amounts of carbs to replenish carbohydrate stores in the body. It is this cycling in and out of ketosis that most people seem to respond best to.

The best carb sources are those that I mentioned earlier in this article: organic berries (blueberries, raspberries, blackberries, etc.), beets, carrots, sweet potatoes (especially purple), pumpkin, sprouted quinoa, and other fruits like apples.

Many people admit that this cycling is extremely sustainable and satisfying to do on a weekly basis.

Your Metabolism On A Ketogenic Diet

Weight loss doesn’t always equal fat loss.

When you lose weight, muscle mass tends to be reduced as well.

However, what you really want to lose is body fat, both subcutaneous fat (under the skin) and visceral fat (around organs).

Losing muscle is a side effect of weight loss that most people don’t want.

Another side effect of losing weight is that the metabolic rate tends to decrease.

You NEVER want to sacrifice your metabolism for losing weight. The goal should ALWAYS be fat loss, which is why it’s important to focus on getting a healthy metabolism.



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