Donating Blood on a Keto Diet? We Asked The Experts.

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Donating blood is an incredible community service but many people on a Keto diet are unsure if they can donate. Honestly, I’d never even questioned whether donating blood was appropriate for people who are ketogenic until someone in my Keto diet group on Facebook asked.

I’ve researched all the aspects of giving blood from a Keto perspective, including contacting the Red Cross to ask specifically about donating while on a ketogenic diet. I want to share this important information with you.

Can you donate blood on Keto? You can donate blood when you are on a ketogenic diet. Ketosis won’t affect the quality of the blood, and giving blood will not affect ketosis. You need to take your own Keto friendly snacks and drinks so you can avoid the sugary carbs they normally offer you after donating blood!

There are some things to think about before you donate, including what to eat or not eat. And you’ll want to be prepared, both physically and mentally. Read on so you’ll be armed for success while you provide your community with such a valuable resource!

Can You Donate Blood If You Are Eating A Keto Diet?

According to the American Red Cross, to donate whole blood you need to meet the following requirements: Be In Good Health, At Least 16 Years Old, and Weigh At Least 110 lbs. If you are virus-free and have no contagious diseases and you meet the age, height and weight requirements, you are eligible to give blood. Even people with chronic health conditions like diabetes and heart disease can donate!

I wrote to the Red Cross and asked specifically if a ketogenic diet and being in ketosis is safe and appropriate for a blood donor. The Red Cross representative replied that ketosis “will not defer you from donating blood.”

Keto on, blood donors!

When you go to give blood, they will first take your pulse, temperature and blood pressure. They will also ask you about your general health and medications you may be taking.

If you feel well and are within the parameters of these simple tests, you can donate!

Does Giving Blood Affect Ketosis?

For people on a ketogenic diet, donating blood will not affect ketosis.

Ketosis is a metabolic state, controlled by your hormones and the interaction of your body with the foods that you either do or do not consume. While you are in ketosis, your body is producing ketones and they circulate in your blood.

So while you will be giving up some ketones when you donate, don’t worry! Just like with other fuel sources that the human body uses, your body will adjust to the loss of blood and replenish your supply.

When you give blood, the amount given is about 10% of your blood volume. You’ve got plenty of ketones in the 90% of your blood that is still circulating in your body to fuel your needs.

It will take your body a little time to recover and replenish that blood, just like it does for people who are not in ketosis. Taking care of yourself before and after you donate is vital to this process, and we’ll talk about that more below.

Will They Test For Ketones in Donated Blood?

After you donate, your blood is tested for infectious diseases to ensure safety in the blood supply.

These tests are regulated by the FDA, and they include HIV, hepatitis, syphilis, and West Nile virus. {Click here for reference. >> } If you have any of these diseases, they will notify you.

They will also test your blood for typing and Rh factor, which are compatibility factors, and they’ll share that information with you.

They do not test for ketones, cholesterol, glucose or insulin levels. These are not factors for compatibility, and people eating all kinds of diets with varying blood lipid levels can successfully donate blood.

So Keto on and don’t hesitate to donate. You might help save a life!

Drink Lots of Water Before and After Donating Blood

The most important thing you can do for yourself when donating blood is to drink plenty of water. Hydration is the most important part of both preparation and recovery. You’re about to give up a significant amount of blood!

Blood is about 50% water, and you need to get that water by drinking it. Being well hydrated before you go in to donate will help you be ahead of the curve. In my correspondence with the Red Cross, they were sure to remind me to “drink plenty of fluids before any scheduled blood donation.”

But you also need to continue to drink extra water after donation. Replacing the donated blood volume is vital for recovery. Your body will make more blood to replace what you lost, and water is the main ingredient. Drink your water!

There is more to blood than water, though. You can help your body stock up and be prepared for making extra blood by focusing on iron-rich foods ahead of your donation.

What To Eat Before Giving Blood

Before you donate, the most important thing you can do is to eat foods that will help increase your iron stores.

Iron is an essential element found in hemoglobin, the red blood cells that transfer oxygen throughout your body. Having plenty of iron is vital for blood production, so having enough is pretty important when you’re going to be giving 10% of yours and needing to replace it!

The importance of eating iron-rich foods was even emphasized in the correspondence I received from the Red Cross. “Please ensure that you eat a well-balanced iron-rich meal and drink plenty of fluids before any scheduled blood donation.”

In the days and weeks leading up to donating, eating foods that are good sources of iron will help you recover after you donate blood.

According to WebMD, the best iron rich foods to focus on are:

  • Meat
  • Seafood
  • Spinach

That sounds pretty Keto to me! All of these will help increase your iron levels while also being great Keto meals.

There are other, non-Keto food sources of iron, too, but the best sources of iron are animal foods because they contain iron in its heme form, which is the same form that the human body uses. Non-heme forms of iron found in plant foods have to be converted by the body into heme, which is an inefficient process.

One great food source of iron is liver. I am a huge proponent of eating organ meats – they are hands down the best source of many vitamins and minerals that are difficult to get in large amounts through other food sources. Iron definitely tops that list!

One 100 g serving of beef liver (that’s about 3 1/2 ounces) has 4.78 mg of iron {see USDA Food Database for reference}.

A couple of my favorite recipes for liver are Beef Liver with Bacon, Onion and Mushroom and my rich and buttery Liver Pate made with chicken livers.

Other great Keto friendly, iron-rich foods with amounts of Iron Per 100 Gram Serving:

While getting plenty of iron is important, you should remember that blood banks will turn away a donor whose iron levels are too high. This is most often due to a hereditary condition called hemochromatosis {Click here for reference.} While too much iron is not extremely common, if you are concerned, you can test for iron levels with a simple serium iron test through your doctor.

Should You Avoid Eating Fat Before Giving Blood?

There is some concern from people eating a Keto diet that you should avoid eating fat before you donate blood. On the Red Cross website, among their advice for successful donation is the suggestion to avoid “fatty foods like hamburgers, fries or ice cream.”

While these foods do have fat in them, do you notice what else they have? Lots of carbs!

Calling these foods “fatty” shows a nutritional bias, in my opinion. I agree that those foods are not healthy choices, but for entirely different reasons.

Stick to steak or seafood and vegetables, and you’ll be following the Red Cross’s advice and mine, and staying in ketosis at the same time.

Can You Intermittent Fast And Still Donate Blood?

If you practice Intermittent Fasting (IF), you may want to consider taking the day off on the day you donate.

Fasting isn’t going to make the blood unacceptable for donation, but it might make you feel more tired than necessary after donating blood.

Some people can donate fasted and be fine, but if you aren’t familiar with your body’s reaction, I wouldn’t take the chance.

Having a good meal and drinking plenty of water before you donate will help you recover more quickly afterward.

What To Eat After Donating Blood

If you’ve donated before, you know that they always have sugary, carby snacks and drinks available afterward. Do you have to eat those cookies and juice they offer you?

It is commonly thought that you must eat or drink these high carb snacks in order to replenish your blood glucose. What is most important is to replenish your blood volume, though, not blood sugar. The best way to do that is with lots of water.

Among the Red Cross’s tips for success is the suggestion to have a snack after your donation. But what they specifically say is to sit and relax in the recovery area and to have a cookie while you’re there. What they really want you to do is to sit for a while and let your body start to recover. After all, you did just lose a lot of blood!

Do sit and relax. But bring your own snacks! If you feel like having a snack after donating blood, that is just fine. Planning ahead and bringing your own will help you avoid the carby junk they most likely have available.

The offerings at blood donation centers vary, and while most have cookies and juice, some might have some nuts, which would be a decent Keto option. However, you can’t depend on them having anything Keto.

Some easy Keto friendly options you can bring:

  • Beef Jerky
  • String Cheese
  • Nuts
  • Seeds
  • Canned Sardines
  • Pickles

For some people, the temptation of the snack table is really tough. Having your own snacks will help you stay on track. This goes for drinks, too. Water is the best to drink, but if having a sugar-free electrolyte drink like Powerade Zero will help you steer clear of the fruit juice, bring it with you!

If you do decide to eat the snacks that are offered, don’t beat yourself up. It’s not the end of your Keto diet! While you may jump out of ketosis for a bit because of a high carb snack or drink, all you have to do is go back to eating Keto after you leave.

Once your body has burned through the glucose from your carb adventure, when there are no carbs left, it will switch back to burning fat and ketones. If you’re new to Keto, this can take a day or two. But the longer you Keto, the easier it is and the faster your body gets at making the switch.

If you want to learn more, here is an article I wrote about how a cheat day affects your keto diet.

Be aware when you are donating that your body may react differently than it has when you donated before going keto.

I’ve heard from some people that they find donating blood has stronger after-effects when Keto. (More light-headed, dizzy, fatigued, etc.) Yet others breeze through it easily.

Regardless of how you react to giving blood while on keto, it’s okay! Listen to your body. Sit and relax for a while after your donation so you can know for sure how you are reacting before you go on to the rest of your day

Will Donating Blood Help You Lose Weight?

There are some people who think that donating blood will help them lose weight. This is a myth! You are taking a significant volume of blood out of your body and that blood has mass, so it may cause a very small dip on the scale. This is not the same as fat loss, which is what you want for healthy weight loss.

Just because the number on the scale changes does not mean that you are “losing weight.” The scale is not your friend! It can’t differentiate between fat, water, blood, inflammation or any of the many other factors that affect your always fluctuating body mass.

Evidently, there was also a small article written in 2001 in Transfusion Magazine that touted weight loss as one of the benefits of donating blood. That article has since been removed and can no longer be found! In it, the author suggested that your body burns extra calories to replenish your blood supply, about 600 calories for a pint of donated blood.

However, the process to replace your pint of donated blood takes 4-6 weeks, which is why they only let you donate once every two months. That means the calorie burn for producing blood is spread out over that time period. That works out to about 15 calories per day.

Your health is more important than trying to use blood donation as a means of weight loss. Focus on the good you are doing. Sharing your blood may save someone’s life. It may not make you lose weight, but it might make you a better person.

Keto on, my friends. Give blood when you can. And treat yourself to a steak afterward! You’ve earned it.


Angela Davis

I'm Angela Davis, Co-Founder of Advantage Meals. I have a Bachelors in Anthropology and Masters in Holistic Nutrition. My passion is Ancestral Nutrition and for over a decade I've been helping Keto Diet beginners and those looking for their Primal Diet. "There is no one right way." Below are the most recent articles I've written for

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