Keto Diet 101: KETO FLU

If you are producing ketones and feeling fine, skip this post and the other blogs that begin with KETO 101. These KETO 101 articles review what can go wrong when you start a keto diet.

However, if you tried to produce ketones and you never turned your ketone test-strip pink, read these posts. If you succeeded at keto for a time, but then something went wrong, read these KETO 101 posts.

If you are a worrier and you read on the internet all the ways this ‘crazy’ diet supposedly messes up your body, read this.

Keto-recap: A body fueled by sugar is chronically inflamed and in crisis. It is impossible to drip in the exact amount of carb fuel needed without going over or under your requirements. More than a teaspoon of carbs pushes your body into releasing insulin. When glucose is your fuel, eating too little leads to a steady decrease in your metabolism. Conversely, extra, unused glucose, rings your ‘insulin alarm’ triggering a spike of this hormone and continuing the cycle of inflammation.

Fueling your body with fat means no insulin. You rid yourself of the crisis. Your body produces ketones from fat when the glucose falls low enough. Ketones slip through your system and body putting out fires of inflammation the longer the ketones are around. A state of ketosis reverses inflammation caused by chronic high insulin levels.

As an internal medicine doctor, my job is helping with your health’s ‘long game.’ In other words, chronic disease management. When your body swells on the inside, that inflammation causes trouble. Chronic, slow-growing inflammation creeps into more and more areas of your body.

After years of too many carbohydrates, your system gets really messy on the inside. But it is stable. Your cell walls become stiff and inflexible. The ‘hoses’ that carry your blood are crusty and can’t be easily stretched or relaxed. Reversing this chronic problem is tricky. The day you flip your energy source from carbs to fat, your body chemistry changes. This sends your crusty, stiff-albeit stable-system into flux.

What can go wrong when a carb addict switches to ketones?


  • THIS PROBLEM AFFECTS PATIENTS: On Day 2 of producing ketones
  • THIS PROBLEM LASTS UNTIL: Lasts for up to a week.

If you Google any side effects of the Keto Diet, keto-flu tops the list of search results.

This condition got its name because chronically inflamed patients experience flu-like symptoms as they transition. Yep, give up those tasty, sweet carbs, and you will feel like you have the flu. When you get the flu, a ‘bug’ sets up a colony or home inside your body and messes with your system. Those critters invading your body cause lots of symptoms. The invading infection steals your water, drinks your salts, and eats up your sugar. Your tummy aches, in part, because the bugs selected your guts as their new home.

Flu symptoms include a headache, tiredness, dizziness when you stand up, racing heart, nausea, loss of appetite, and feeling rather irritable. When you get the flu, you get dehydrated. That dehydration causes all those symptoms. A body switching from sugar to fat also gets dehydrated. Dehydration causes the symptoms collectively called ‘keto flu.’

What’s so dehydrating about producing ketones? Ketones aren’t the cause. Instead, it’s the lack of all those glucose molecules circulating in your system. Glucose is a large, monster-sized molecule that flows through your veins.

Glucose acts like a sponge and holds onto water as it percolates throughout the body. Each glucose molecule holds onto hundreds of water molecules. Excess bloodstream glucose translates to thousands – even millions – of extra water molecules.

Do the math.
Check your blood sugar. Is it above 100? For every point above 100, you added thousands of extra monster-sized glucose molecules to the 7 liters of blood you hold. Now, multiply that by the hundreds of water particles clinging to each glucose.

Twenty carbs per day lead to way less glucose in your bloodstream. Less glucose holding onto that circulating water causes you to flush that extra fluid out. Over the course of the first week, I have had patients lose 20 pounds. That’s nearly three gallons of excess water.

Removing the extra water causes significant weight loss. KETO or the ATKINS diet gets picked on through statements like this: ‘The only way you lose weight on a high-fat diet or Atkins-like diet is because you lose water weight.’ That’s exactly what happens….at first.

Millions of water particles lost their chemical sponges and are gone. Without that sugar, the water flows right out the kidneys. Dehydration is defined by the rapid loss of water. All that extra water inflames or irritates your body. Removing it is the right answer.

Your ‘flu’ or dehydration symptoms appear when you are caught unprepared for ketosis’ water loss.

This water loss hits your kidneys like a tidal wave. Your kidneys remove water from your blood by adding it to your urine. They ‘steal’ salts from your bloodstream to make this happen.

Before long, you get a headache and feel really tired. You try to stand up only to suffer sudden dizziness and a pounding heart. Oftentimes, you get crabby. Welcome to the keto flu.

The antidote is simple: eat SALT, drink water and slow down.

Let’s start with salt. Yes, I mean salt. Like the white stuff in the shaker on your table. I prefer pink Himalayan salt or sea salt, but common table salt will do. Salt, like fat, is an overly demonized compound.

Fat and salt are essential to the Keto diet. You need to replace the fluid that belongs in your body. Knowing that keto transition sucks salt and water into your urine should motivate you to add salt to anything you eat or drink.

You get dizzy because there’s not enough fluid in circulation. Replace that fluid by eating and drinking with salt.

If you add plain water back to your system, you will not fix the flu-like symptoms. The water will go in and flush right back out. The salt holds the proper amount of water in your circulation and corrects the dehydration. Drink salty broth to keep the keto flu away!

The next step is to slow down.
If you are reading this and considering fueling your body with fat, GREAT. Let me help you succeed. If you are a carb addict with a daily intake of more than 300 carb gram, start slowly.

Begin with zero calories in your drinks for the first week. Once you are successful with that for seven consecutive days, then remove all white foods: No bread, no rice, not pasta, no pastries. Follow that rule in addition to the no-calories in your drink for seven straight days as you prepare for ‘transition day.’ This plan gives you the space to allow a gentle shift in your body chemistry to prevent the keto flu. This schedule also gives you enough time to clean out your cupboards.


  • THIS PROBLEM AFFECTS PATIENTS: On Day 2-3 of producing ketones
  • THIS PROBLEM LASTS: up to a week.

If you are on blood pressure medication and you want to get off them, the keto lifestyle is the answer. However, the transition can be dangerous. Prepare yourself.

My patients taking high blood pressure meds must check their own blood pressure at home. Without all those large glucose molecules loaded with hundreds of additional water particles, your body’s circulation volume drops. Not because of blood loss; because of water lost. Lower volume means less pressure! It takes far less medication to control blood pressure when all that water is gone.

Thanks to the Keto diet, helping patients get off blood pressure medication has never been easier. You must use a home blood pressure monitor though. Check your blood pressure 2-3 times a day when transitioning. As you reduce and remove carbohydrates from your diet, your blood pressure will drop quickly. Be careful. Let your doctor help you remove those blood pressure medicines as quickly as you remove the carbohydrates.

In a matter of five days, I got one patient off of five of his blood pressure meds! This, of course, all depends on how strict you are at following the less-than-20-carbs-a-day rule and how long you have been a carb addict.

When your heart races inside your chest, a feeling of terror takes over your mind – even if you are a doctor. Your fear is justified. A pounding heart can be a warning of impending death. It signals us to pay attention. If your heart begins to thump inside your chest during ketosis transition, pay attention. Your body is warning you of something.

The most common reason for this symptom is the dehydration mentioned above. Dehydration forces your heart to pump fast and strong. Fix this problem quickly by drinking salted water! Keep doing this until the heart-pounding goes away.

If you have a history of heart arrhythmia or heart failure, you must consult your doctor before you go on a keto diet. If your heart is pounding because of an abnormal rhythm, you can drown yourself in salted water only to make things worse for your heart.

Check out the book ANYWAY YOU CAN on Amazon or Audible by Annette Bosworth, MD for more keto information.


  1. Seyfried, Thomas N. Cancer as a Metabolic Disease: on the Origin, Management, and Prevention of Cancer. Wiley-Blackwell, 2012
  2. Siri-Tarino, P. W, et al. “Meta-Analysis of Prospective Cohort Studies Evaluating the Association of Saturated Fat with Cardiovascular Disease.” American Journal of Clinical Nutrition, vol. 91, no. 3, 2010, pp. 535–546., doi:10.3945/ajcn.2009.27725.
  3. Effect of exercise intensity and starvation on activation of branched-chain keto acid dehydrogenase by exercise; G. J. Kasperek, and R. D. Snider; 01 JAN 1987.
  4. Scott AR1; Joint British Diabetes Societies (JBDS) for Inpatient Care; JBDS;Management of hyperosmolar hyperglycemic state in adults with diabetes; Diabet Med. 2015 Jun;32(6):714-24.   DOI:10.1111/dme.12757

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