Start and First Month
The hardest part of the transition is not a month, but the first three days. During these days, your mood drops, you crave sweets, and you get a headache: your body is switching from sugar to fat. It gets easier after that, and the main thing at this moment is to eat properly and drink enough, rather than endure it.
Five steps of transition
Remove fast sugar from the kitchen
Sugar, bread and baked goods, grains, potatoes and corn, sweet fruits, juices and soda. As long as these are on the shelf, the decision is made anew every evening.
Buy the basics
Greens and salad, avocado, eggs, fatty fish, olive oil, nuts, sauerkraut. That’s enough for the first week without overthinking.
Build your day around three meals
An 8–10-hour window, for example 10:00, 13:00, and 18:00. Nothing between meals: there are no snacks in the method.
Get your hydration on track
Aim for around two liters of fluids a day, and more in hot weather and on training days.
Do not add a second break
A new training routine, vacation, moving, and starting a nutrition plan all in one week — that’s not willpower, it’s a guaranteed derailment.
The first three days: what usually happens
The reaction varies greatly from person to person, and there is no single pattern. But most often, it looks like this.
On the first day, familiar hunger at regular mealtimes and cravings for sweets are noticeable. On the second, glycogen is used up, and along with it, the water bound to it: headaches, weakness, dizziness, and a rapid drop on the scale during these days are possible—largely water, not fat. By the third day, some people experience fatigue, reduced concentration, and changes in bowel movements.
The so-called “keto flu” symptoms occur far from everyone and last from several days to several weeks.
It’s only difficult for the first 3 days. Your mood may drop and apathy may set in. This is the body’s temporary resistance.
What helps during these days
- Eat normally: protein, vegetables, enough energy
- Drink enough fluids
- Do not combine the start with a severe calorie deficit
- Don’t push yourself too hard with workouts
- Sleep as much as you can
Stomach adaptation: start with half
If there used to be little fat in your diet, start with half or a third of the recommended fat portions and increase gradually.
Heaviness after lard or bacon means the portion should be reduced by half. Bloating from sauerkraut is treated the same way: a smaller amount, and if it is not tolerated, replace it with bell pepper and apple cider vinegar.
What to do after a lapse
Don't compensate for it. Return to your usual routine with your next meal.
A dessert at four in the afternoon does not ruin the day. The planned dinner remains a regular dinner, followed by the usual overnight break. The answer to the question “how many hours before returning” is—not 12, 24, or 36, but with the next normal meal.
Don't “eat your way through the rest of the day just because you've slipped up.” And especially don't punish yourself with a day of fasting afterward. It is the familiar routine over weeks and months that makes the difference, not one episode.
Frequently asked questions during the first month
When will the swelling go down and energy levels even out?
There is no strict timeline. In the first few days, some fluid is lost due to reduced glycogen, and during the first one to two weeks, many people experience a decrease in initial headaches and weakness. There is no established timeline for steady energy and reduced cravings for sweets: for some, it happens quickly, for others, noticeably later. The first noticeable changes often appear within one to three weeks, but this is not a criterion of success.
When should you switch from three meals to two?
When for several days in a row one meal really isn’t needed: there is no weakness, no obsessive thoughts about food, no evening overeating, and the protein and calorie needs are covered by the remaining meals. First, it is worth stabilizing the routine for at least one or two weeks.
Should you aim for one meal a day?
No. One meal has not been proven to be better than two or three full meals, and it is noticeably harder to get enough protein, fiber, and micronutrients from it. Two meals is a perfectly reasonable endpoint if it feels comfortable.
Can I work out during the first week?
Light activity — yes. Starting a new training routine on the same day as changing your diet — no: two sources of fatigue add up, and people usually give up on both.
What to do tomorrow morning
- Tidy up the kitchen: remove fast-acting sugar
- Make a shopping list for the first week
- Set times for three meals and write them down
- Put water on the table
- Postpone starting new workouts for two weeks
Reviewed by Anastasia Zhukova, Fitness Trainer • Author of a Nutrition and Training System • Creator of an AI Personal Support Platform
A human has reviewed this material against the method and real client practice.