When You Eat Keto…This Happens Inside You [Step By Step]

When You Eat Keto…This Happens Inside You [Step By Step]

Video | Downloadable Chart | Day 1 | Day 2 | Day 3 | Day 4-7 | Day 8-30 | Day 31-40 | Day 41-90 | Day 90+

When you switch from eating a high-carb diet to a keto diet, your body is forced to adapt. In this post, we’ll take a deep dive to see what is happening inside you in the days, weeks, and months after you go keto. 

When You Eat Keto…This Happens [Downloadable Chart]

Download a Copy of This Chart Here

(Download a copy and hang it on your wall. It will act as a great motivator to help you to stick with your diet!) 

When You Eat Keto…This Happens [Video]

In this video, you’ll learn…

  • Why you may feel fatigued after starting a keto diet.
  • What happens inside your body when you switch to a keto diet.
  • Encouragement for moving forward and pushing through the beginning stages of your new diet!

Eating Keto

As you likely know, a ketogenic diet is a very-low-carb diet. The number of carbs you can consume and still be considered keto will vary depending on your metabolism, but the uppermost level is no more than 50 grams of total carbs per day. 

Day 1 of Keto

From Day 1, your body will be reacting to the change in your food intake. Because carbohydrates get broken down by your digestive tract into simple sugars that are then transported to your bloodstream, drastically reducing your carb intake leads to lower blood sugar or blood glucose levels. This is the start of a cascade of events.

For starters, the low blood sugar leads to lower levels of insulin in the blood, which signals the kidneys to accelerate the excretion of sodium or salt from your body. Water tends to follow salt, so you may notice a reduction in water weight from Day 1.

However, this loss of water and salt can also leave you feeling tired, irritable, mentally foggy, and hungry. These symptoms are so common that they’ve been given the nickname the keto flu. 


One of the advantages of the keto diet is that it teaches your body to be less reliant on sugar for energy, and instead run on fat and ketones. However, this fuel switch does not happen right away.

On this first day of your keto diet, your liver needs to pick up the slack and create glucose to keep your blood sugar at a sufficient level to run your body. Fortunately, your liver is very capable of this task and has stored away glucose in the form of glycogen for times just like these. By breaking down those glycogen stores, your liver maintains your blood sugar at a safe level.  

Day 2 of Keto

Your liver saves the day at the beginning of your diet. However, the glycogen stores are limited, and as you move into Day 2 of your keto diet, your body needs to search for fuel.

Fortunately, the low insulin level you are experiencing makes it easy for your fat cells to release fat. Therefore, as long as you are not eating excess calories, your body begins to tap into your fat cells for fuel. When this happens, the triglycerides in the fat cells break apart, releasing free fatty acids and a molecule called glycerol into your system. 

Day 2 of Keto

Day 3 of Keto

As you finish Day 2 and move into Day 3, many of your tissues, including your muscles and heart, are taking in free fatty acids and utilizing them for energy. However, your brain is a different story. It can’t use the fatty acids directly, so your liver must come to the rescue again.

This time, it saves you by converting some of the free fatty acids into ketones or ketone bodies, which are a form of fuel that your brain loves and the hallmark of a keto-genic (literally meaning ketone-making) diet. It is these ketones that can be detected in the urine or blood. When they are present at a sufficient level, you are in nutritional ketosis. 

Day 3 of eating keto

Days 4 – 7 of Keto

As the week progresses and you continue to eat a very-low-carb diet, your body is hard at work creating the enzymes and metabolic pathways that it needs to become a more efficient fat burner.

These adaptations not only accelerate fat loss but also allow you to experience more energy and mental clarity, as the symptoms of keto flu subside.

The transformations also make you more metabolically flexible, meaning that your body can more easily switch between the available fuel sources, which now include free fatty acids, ketones, and glucose, which is supplied by your diet and liver. 

(Side Note: On a keto diet, your liver continues to provide glucose through processes like glycogenolysis and gluconeogenesis. Glycogenolysis is the breakdown of glycogen. Gluconeogenesis is the creation of new glucose from things other than carbohydrates, such as glycerol, fatty acids, and protein.)  

Day 4-7 of eating keto

Days 8 – 30 of Keto

As you move into the second week of your keto diet, your body has become efficient at running on stored energy, which reduces hunger and makes intermittent fasting easier to perform.

However, while your body may be getting into the groove, there are environmental cues and emotional ties to high carb foods that are likely still hitting your awareness. Therefore, during this relatively early stage of your diet, it pays to stay focused.

If you give in to temptation now, you’ll be quitting just before the magic happens. Keep going through the first full month, and you’ll gain physiological changes that make it harder to return to old habits.

Day 8-30 of keto

Days 31 – 40 of Keto

By the end of the first month, new benefits appear thanks to the prolonged time that you’ve spent away from sugar and sweetness. Research suggests that taste receptors as well as receptors in the pleasure center of the brain, down-regulate when they are exposed to intense sweetness on a regular basis (1) (2) (3).

That’s not good because it intensifies sugar cravings. Since you’ve been sugar-free for a month, these receptors reset, allowing you to experience fewer sugar cravings and detect a wider range of flavors, adding to the enjoyment of your diet. 


Days 41 – 90 of Keto

As you continue through the first three months of your keto diet, the reduction in the level of hunger that you experience leads to a subconscious reduction in how much you eat.

This factor, along with the consistently low insulin levels, leads to a noticeable loss of visceral (abdominal) and subcutaneous (under the skin) fat. Because carrying too much visceral fat has been linked to a higher risk of type 2 diabetes, heart disease, and certain cancers, you’re gaining health as you lose weight.


Days 90 and Beyond of Keto

By the end of the first three months of following a ketogenic diet, many people feel as if they have found a secret weapon that keeps them feeling energetic, alert, and satisfied as they continue to lose the excess pounds of fat they’ve been carrying.

By this point, the body has become fat-adapted. Any drop in athletic performance experienced in the first months of the diet have been reversed, and your body has become better at using fat for fuel during exercise and throughout the day. 



When you switch to a keto diet, essentially, what you’re telling your body to do is become less dependent on sugar and instead use fat for fuel. This switch will not happen overnight, so the start of your keto journey can be a bit rocky. However, the rewards will come if you stick with it!

Thanks for reading and have a wonderful week!


(1) Wise, Paul M., et al. “Reduced dietary intake of simple sugars alters perceived sweet taste intensity but not perceived pleasantness.” The American journal of clinical nutrition 103.1 (2016): 50-60.

(2) Sartor, Francesco, et al. “Taste perception and implicit attitude toward sweet related to body mass index and soft drink supplementation.” Appetite 57.1 (2011): 237-246.

(3) Rada, Pedro, N. M. Avena, and B. G. Hoebel. “Daily bingeing on sugar repeatedly releases dopamine in the accumbens shell.” Neuroscience 134.3 (2005): 737-744.

About the Author

Becky Gillaspy, DC graduated Summa Cum Laude with research honors from Palmer College of Chiropractic in 1991.

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