Four weeks of a strict keto diet and ketone monitoring

Can ketone measurement help you lose weight and improve performance? That’s the main question I’ll be trying to answer with my four-week experiment.

See Report #1 for diet and experiment design.

Note: This experiment was done six months ago and initially only reported on my Swedish blog. This is a somewhat delayed translation!

Below are graphs of my weight and waistline over this first four-week period, as well as the results of blood and urine ketone measurements.


After two to three weeks of light nutritional ketosis, I’ve now spent 8 days in “deeper ketosis” – that is, between 1.5 – 3 mmol/L. Want to know what’s happened?

The effects of higher ketone levels/h3>


Although happy with my weight before this experiment, I’ve become noticeably leaner: -4kgs (9 pounds) and -6cm (2,5 inches) around the waist. This, of course, in complete absence of hunger – in fact, I’ve seldom felt so constantly sated. Food is tasty to eat at mealtimes, but I can skip a meal without even blinking.

My weight – initally 100kgs – was already well within normal range, considering I’m 202 cm tall – 6 feet 7 inches – and do strength training regularly. The other measurement I kept track of was my waistline. 94cm or less around the waist is considered excellent for men; I started out with 91cm, and am now around 85cm (33 inches). I need to punch a new hole in my belt, which means I’m leaner than I’ve been in a very long time. Not bad for a forty-year-old father who has limited time to work out and always eats his fill!

Mental effects

Being the father of a small child, I often get tired from lack of sleep, and during the first week of the experiment I sometimes felt even woozier than usual. This is natural while the brain adapts to running on ketones.

The last two weeks brought everything back to normal again. Or perhaps I even felt sharper and found it easier to focus for longer periods of time? Hard to tell. Perhaps it was just my imagination.

Some people have mentioned having more colourful, dramatic dreams when in ketosis – at least during the first period. I actually think this was the case for me during the first couple weeks, too.


Due to a tight schedule, my exercise has been limited to one short weekly strength routine at the gym, in the style of “Body by Science”. I take note of the weights and times I manage though, which makes it easy to compare my weekly performance.

  • The first session, following one day of strict low-carb, was nothing out of the ordinary.
  • The second and third sessions, after 7 and 17 days respectively, showed a marked performance decrease. My muscles tired more quickly.
  • The fourth strength training session, 26 days in, showed a better result than when I started.

Just as I had expected, exercise was tougher the first weeks of strict LCHF. However, four weeks in I was back at my original strength level – despite losing weight.

The combined result of less body fat while keeping (or slightly improving) my strength level reminded me of the new study conducted on elite gymnasts. Being stronger with less body fat is certainly much coveted by athletes.

Other early effects of ketosis

Another thing I noticed during the last week, i.e. during the most pronounced ketosis, is the diuretic effect. I was copiously leaking ketones (as is evident from the urine ketone levels), which take a lot of water with them going out of the body. A few of the days I drank lots of water trying to quench a stubborn thirst, and consequently paid frequent visits to the bathroom. My mouth felt dry no matter how much I drank.

Today, this is much less noticeable. Perhaps my body is adapting. Many people seem to stop leaking ketones through urine in the longer term, coupled with still being in ketosis according to their blood ketones. I’m excited to see if the same will happen to me.

A similar trend can be noted with the breath issue. The first days or weeks of ketosis, many exhale small ketone bodies, acetone. Ketosis breath has an odour reminiscent of fruit (that’s putting in nicely – others put it right up there with rotten apples), and may also be reminiscent of nail polish removers (which often contain acetone). If you find yourself experiencing this, bear in mind that it generally disappears in a couple or several weeks*. I’ll just wait and see if that’s true for me too, as I’ve had that kind of breath once in a while.

Sense of taste

Another interesting thing I’ve heard people mention during ketosis is the way they experience sweet tastes. For my part, I never drink soda and almost never eat any kinds of sweets as it is. I do however tend to enjoy fruits and berries regularly. Of course, striving for higher ketone levels means completely abstaining from everything sweet, and after doing so for a couple weeks, I one day mindlessly ate a piece of banana my daughter gave me. It felt like an explosion of sweetness. The fewer sweet things you eat, it seems, the more your sense of taste adapts.

The same principle appears to work the other way as well. Those addicted to sugar and used to consuming large amounts of sweets/artifical sweeteners daily, will have a hard time registering the sweetness of something only fairly sweet.

Transition troubles

From what I’ve read and heard, the first week of strict LCHF seems to commonly bring headaches, dizziness, tiredness, palpitations and irritability. I felt none of these things, save for a slight “woozy” feeling on some of the first days. This is probably because my everyday liberal LCHF diet should mean already I’m partly ketone-adapted. The lack of heavy transition troubles can also be because I took care to stay hydrated and get enough salt, which usually keeps the worst symptoms at bay.


This is going well so far.

  • Weight loss without hunger, even down to being very lean. It’ll be interesting to see where my weight stabilises; I’m guessing, pretty soon.
  • An overwhelming sense of satiety, which is quite practical if you don’t have time to constantly be eating.
  • The exercise routine seems to be running smoothly now that I’m a few weeks in.
  • My mental focus feels at least as sharp as before.
  • On the downside, there’s sometimes been a pronounced diuretic effect, and ketosis breath once in a while. Hopefully, these will disappear with time.

I’m going to keep this going for a while more, to try and experience the full effects of ketosis, and also to be able to perform some interesting and accurate experiments with different types of food and ketosis. More reports to come!

Previous related posts:

Lose weight by achieving higher ketone levels

A new toy measuring blood ketones

The ketone master has arrived

A keto diet for beginners

Experiment: Higher ketone levels for weight loss and improved performance

*/ For some individuals, this might not even disappear in the long term. If you’re one of those, and decide you don’t want to go around constantly smelling of ketosis, or rely on a constant supply of breath mints, you’ll probably have to settle for a more liberal LCHF diet. That is, eat some carbohydrate; around fifty grams or more a day will keep ketosis away. Unfortunately, this is a compromise, meaning you won’t be getting the maximal effect of your LCHF diet.

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