What I’ve learned about Ketogenic diet

First, a disclaimer: I’m not a doctor. Don’t believe anything I say. Before doing anything with your own body that you might regret later, talk to a real doctor.

A lot of people ask me about Keto diet and it seems that it will be a better use of my time to write this down rather than repeating the same things multiple times, so here it goes:

A while back, I decided to try this diet. I was never a diet kind of person. My weight at the time was 185 lbs, at 5’11” it’s not like I was desperately looking for losing weight or anything. So, why did I do that? The short answer is health benefits, but I’ll go in more details further below.

Anyways, after reading a little about it, I told myself: “alright, I’ve got this” and started doing it. Here’s some of the results I’ve got:

Before you ask:

  • Yes, that measure is consistent with others made via different instruments.
  • Exercise routine:¬†About 3 times a week, half an hour each, weight lifting only. The rest of the time was mostly spent sitting at work in front of a computer.
  • I stopped at around 12% body fat because I started adapting to that new routine and didn’t feel the need to go any further down that path.
  • I’m over 40. Now I’m just bragging ūüôā

In 3 months, my body fat dropped from 20% to 13%. Actually in the first month alone I seem to have lost close to 20 pounds (Remember: I wasn’t even trying to lose weight. This was just a side effect that lead to my colleagues at work asking if I was OK all the time). So, I went from about 185 lbs to 165 lbs, very quickly, which made me worry that if I was going to stick with this, I probably had to figure how to not disappear in the process.

What the heck is Ketogenic diet?


Again, I’m not a doctor or a scientist and what I will describe here is my understanding of the whole thing. Do yourself a favor and read more reliable sources if you want to go deeper into the topic.

Keto diet is a high-fat, moderate-protein, low-carb diet.

Imagine your body is a hybrid car and it can generate power from two sources: Gas or electric. Except in our case, that’s carbs and fat, the sources of energy we use. Normally, we run on carbs by turning them into glucose. Insulin is then produced to process that glucose.

Your body will pick carbs over fat to generate energy any time it can, for obvious reasons: Fat is how energy gets stored, so it can then be used later if your body doesn’t have another option. Best way to increase more fat in your body? Eat more carbs than you need. Yes, it is not eating fat that makes you fat: Fat is the byproduct of the excess of what you eat. So most of those “low fat” products do little to help you and often a lot to harm you.

Usually on a keto diet you will keep your daily consumption of net carbs below 20g. Net carbs are the total carbs minus fiber. There is a lot of controversy here because some products will lie to you on their labels about this. What all of that means is that by the end of the day, what you are trying to avoid is the production of insulin: Fiber moves slowly through the digestive system and often isn’t digested, which is great because fiber is the kind of carbohydrate that doesn’t count as net carbs. Sugar is the opposite of that and will spike your insulin right away. Then there are sweeteners, alcohol sugars and they are all different. Some will be causing as much damage or worse than sugar while others won’t, except labels won’t tell you anything about it and will lie to your face about being “low net carbs” where they will still throw you out of ketosis easily.

Why is the 20g the magic number for net carbs in keto diet? It isn’t. It depends on your body. Some people can handle 30g or even more. Your genetics, age, how active you are physically… all count here. So 20g is a low enough, “just to be safe” number. At least in the beginning you want to keep that number in mind.

What the heck is Ketosis?


When your body runs out of carbohydrates, it will then deplete its glycogen stores. It now needs to convert fat into ketones, also known as “ketone bodies”, the byproduct of breaking down fat to create energy. Ketones are of 3 types:

  • Acetoacetate (AcAc), let’s call it step 1 from fat into energy
  • Beta-Hydroxybutyric Acid (BGB): Formed from acetoacetate
  • Acetone: Also created from acetoacetate. It is also the cause of that lovely bad breath you get when you’re in ketosis (oh yes, that comes with the package, but there are ways around that)

Both Acetone and BHB transport energy from the liver to the rest of the body. If your body is doing that, we say it’s in ketosis.

This sounds wonderful, how do I start?


When you start with the ketogenic diet, you will feel awful for the first days. Your body is depleted from glycogen, but it doesn’t know very well how to break down fat into ketone bodies yet. So for a while, it just doesn’t have enough energy. You will feel weak, your mind will feel confused (turns out brain also needs energy). We call this keto flu.

After a while (time varies, but usually within a week you should see that change. Some people don’t even notice a real keto flu) you start feeling better and that’s when the fun starts.

When you use carbs as energy source, that energy supply oscillates. You eat, you feel sleepy, then you feel better, then you feel hungry and weak again, then you eat, etc. But in ketosis, your energy supply is more constant. You always have energy. In fact, you can even go without eating for hours, days, and still feel enough energy to work, exercise and so on. It is not uncommon to see people who do keto also doing what we call intermittent fasting.

You also don’t feel hungry all the time. The body is not desperate to find energy anymore.

A few things to keep in mind as you start:

  • Don’t panic for feeling weak in the first week. It’s the keto flu. Some people try taking exogenous ketones to help with this. I personally don’t see it as necessary and not everyone thinks it’s a good idea anyways.
  • You will pee more than normal, at least in the first month or so. For every gram of glycogen stored, you have 3g of water also stored. So your kidneys will start excreting more water, which explains part of the quick weight lost people experience at first (yes, it will slow down later, see how my chart went above). But with that water you also lose minerals, the famous electrolytes. You need to replace them, or else you will start feeling the symptoms of low electrolytes. Symptoms such as heart palpitations, feeling shaky, dizzy, having migraines, cramps, etc. If that’s happening, now you know why.
  • At first you can check whether you’re in ketosis by using ketone strips. They are like pregnancy tests you do with urine and will give you a color result based on the reaction from the ketones in your urine. But there’s a catch: Over time, they will stop working. That’s good news: Your body is adapted and is not wasting ketones in your urine anymore. At that point you should be intimate enough to the whole ketosis to kind of “just know” your body is doing it. You don’t need to measure all the time anymore. If you really, really feel like it, there are home blood tests you can buy, but they are expensive and again, why bother? You know the routine now.
  • You don’t get to eat a lot of protein, because too much of it throws you out of ketosis (remember, if your body needs to release insulin to deal with what you eat, you’re done with ketosis. There are things beyond just eating carbs that can cause that). The rate is usually 15% to 30% of calories from protein and 60% to 75% of calories from fat. So if you’re thinking you’re going to have the BBQ life of a king/queen, slow down. Also milk, by the way, is not your friend here.

Why would you do Keto anyways?


I get that question a lot. If I’m not interested about losing weight, then why? Let me list a few reasons, beyond the obvious weight losing one:

  • Most of that fat loss comes from the abdominal area, which has strong correlation with higher heart disease risk.
  • It keeps your triglycerides down, which also reduces the risk for heart disease.
  • Increased level of HDL (the good cholesterol). I should highlight that the bad cholesterol can also go up in the keto diet. But then we could discuss whether this alone is a risk and the fact that it depends a lot of what you eat.
  • Reduces insulin levels, which means low diabetes risk. Patients with type 2 diabetes often can reduce their insulin dosage significantly with this diet.
  • The ketogenic diet is commonly used in patients with epilepsy since the 1920s and has demonstrated to help and sometimes even cure seizures.
  • Increased brain focus, increased cognition, enhanced memory, which obviously helps patients with Alzheimers/dementia. Also has been shown to be effective against Parkinson’s disease.
  • Even helps with autism!
  • Ketogenic diet fights cancer! Think about it: You’re making your body… “recycle” itself, which also can apply to cancer cells. Also, some cancer cells seem to be unable to use ketone bodies for energy, which means they starve.
  • Lower inflammation. It seems that cholesterol is especially dangerous to the heart when associated with inflammation, which is another area where the ketogenic diet helps.
  • Improving endurance for athletes. If you’re into marathons, you might want to consider that. Think constant energy supply.
  • Calorie restriction in general has been shown to significantly extend the lifespan in mice.

There are many more benefits (not sure I agree with all of that, by the way. I don’t think you sleep better, for example. It is well known that people report having a harder time to fall asleep when in keto) and research in this space keeps coming.

Think about it: For thousands of years we didn’t have a fridge, a grocery store, there was no way we could guarantee a constant supply of food. Our body was built for periods of food supply and periods of shortage. That is the “healthy” way for which we adapted. The whole “you should eat 5 times a day” recommendation is highly questionable if you consider all the evidence above.

Likewise, fasting comes along with very similar benefits: It is all about depleting your body from glycogen and you will find similar studies pointing to similar health benefits.

Sounds great but I can’t do that, it’s too hard


There are a few things you should keep in mind:

First, Once you are keto adapted you will feel far less cravings for carbs. You literally feel less hungry. I remember travelling for a conference and couldn’t find low carb food in any nearby restaurant so I decided to go without eating for the 2.5 days of the conference (again, before doing anything, talk to your doctor). I didn’t feel hungry or low energy.

Also, remember to keep the easy temptation away: Remove carb snacks from your house and have other things to fulfill the need when you feel hungry. There’s some good low carb chocolate out there (careful with what kind of sweeteners they use. I noticed¬†Erythritol seems to be quite good).

And if you still feel like you need carbs every now and then, pick one day of the week for cheating. You can gladly plan for it in advance and enjoy it guilt free when it happens.

Another less extreme alternative is intermittent fasting: The idea is to make your body run out of glycogen with frequency. For example, you can stop eating by 6pm and only have your next meal by noon next day. You can combine that with a moderate low carb, but not ketogenic diet where you are allowed to eat some of the things you like.

Also, the time of the day matters: Your body doesn’t handle carbs as well late in the day as it does in the morning: So if you’re going to eat carbs, do it early, not late.

The other trick is to workout, either 30 min before or after eating carbs, it helps.

There are many other “tricks” you can use, all with a variety of levels of risks/benefits, some will raise the eyebrows of your doctor (did I mention you shouldn’t pay attention to anything I say and instead should just go talk to your doctor?).

For example, some people talk about taking Metformin (medication for diabetes), even while not being diabetic, to cause the same effect of controlling insulin. I bet your doctor will say don’t do that.

There are also supplements, like Berberine which are said to cause a similar effect.¬† Again, I’m now talking about the high end of the risky/experimental stuff so probably just don’t.

Other fun side effects of Keto


I didn’t mention alcohol so far so let’s talk about that: Don’t drink it. Alcohol is not a good friend of keto. Beer, wine and others are high on carbs, and even drinks that aren’t rich in carbs like Vodka still mess up with your metabolism, especially if you’re looking into losing weight.

But funny enough, while on keto, alcohol has a stronger effect on you. So if you are the kind of person who can easily handle 4 shots of Tequila normally, go easy before trying that on Keto. You might be surprised with how quickly you will get pretty drunk.

Likewise, medication can act differently. If you take medication, you need to discuss with your doctor about your diet. Chances are your doctor didn’t spend much time studying about ketogenic diet and will default to something like “yeah, probably stop that”. It helps finding a doctor who understands it very well. Either way, be careful with taking medication while doing it, as most medication was designed and tested for people who are… well… addicted to a high carbs diet. By addicted I mean literally addicted, you know the withdrawal symptoms I described above.

After a long time on low carb, you will also notice some funny effects that will happen when you decide to cheat. One morning I had a breakfast with my wife and I had a good sized slice of coffee cake. After an hour or so, I started to feel very weak and my hands started shaking. I mean, really shaking. Later I learned that this was due to increase of insulin sensitivity, which is a good thing:

If you eat a lot of carbs, your body releases so much insulin that it gets used to it. Like a drug. Over time, it needs to produce even more of it so it can have any effect. As a result, your body can’t get rid of the glucose in your blood. Hello Diabetes. And hello a bunch of other problems… I’m talking nervous system damage kind of problems.

At the other end of the spectrum, if you’re in a keto diet for quite a while, your body doesn’t produce insulin a lot, and then if you eat sugary food, suddenly your body throws quite a bit of it on your blood and since the body is highly sensitive to it… well hello reactive hypoglycemia.

Some people also report higher anxiety when on keto. I haven’t had that but know of others who did. In those cases you might eat some carbs later before bed, and also make sure you’re getting your electrolytes.

Fun fact: Some kids in the tech industry are all over this for “boosting brain function”. Except quite a few of them go for intermittent fasting only… and don’t do it frequently enough to be keto adapted. So every time they do it, they feel the keto flu and terribly hungry while still trying to work at the same time with their brains probably at 50%. You’re doing keto wrong, kids…

That’s all? Well, you suck!


Alright, I’m sure I’m missing a lot of stuff. The above is just a summary from the top of my mind. Let’s cover some additional reading/listening references:

  • Follow Dom D’Agostino on Twitter, check his website and listen to his interviews with Tim Ferriss, part 1 and part 2. Amazing amount of knowledge there.
  • Follow Dr. Rhonda Patrick on Twitter. Also great source of info.
  • Speaking of Tim Ferriss, his podcast every now and then talks about keto diet, interviews a few different experts on the topic, always fun.
  • Netflix has the movie “The Magic Pill“, which is interesting to watch

What about you? Any fun facts and experiences with the keto diet?

Also read part II, about what to eat: https://www.matvelloso.com/index.php/2018/07/10/ketogenic-diet-part-ii-what-to-eat/