Did you hear exogenous ketones prevent fat loss on a ketogenic diet?
Because there have been several rumors floating around online that taking exogenous ketones will stop your body from making its own ketones so you’ll never get to burn your stored fat reserves.
Yet most ketoers use an exogenous ketone supplement daily and say it improves their fat burning potential, increases their energy levels, and helps them achieve jaw-dropping weight loss results.
So which should you believe?
Could exogenous ketones be the reason you’re not banking scale victories on keto?
To help you know for sure, I’ll be going over the following topics in this guide:
Before we get to the answer of whether adding EK to your diet is a good idea, you need to know the role they play in ketosis first.
Keto, ketosis, and ketones are all buzzwords you’re likely to hear in ketogenic diet chats and forums, yet many newbies are still unsure of what each one means.
While the first four letters of these words are all the same, they each have different purposes when it comes to reaching your body goals.
Keto is short for the ketogenic diet, which is centered around lowering carbs, eating moderate amounts of protein, and fueling your body with healthy fats to achieve ketosis.
Ketosis is a metabolic state where your body switches its primary fuel source to fat instead of glucose. This means when you’re truly in a state of nutritional ketosis, your body burns fat and starts producing more ketones.
Ketones are energy molecules your body uses just like glucose for fuel — only better. While the glucose roller coaster causes energy fluctuations throughout the day, ketones give you sustained energy and zero crashes.
Your body naturally creates three different types of ketones: acetoacetate, beta-hydroxybutyrate, and acetone.
These are known as endogenous ketones because they’re produced inside (endo-) your body.
Exogenous ketones are ketones made outside of your body but they work the same way and have the same effect as endogenous ketones.
Most exogenous ketones are even made with beta-hydroxybutyrate, or BHB for short, one of your body’s own endogenous ketones.
So now you’re probably wondering why you would need to supplement with exogenous ketones if your body already makes endogenous ones.
When you’re in ketosis, your body has officially switched gears and uses the ketones it produces and your stored fat for energy.
But it can take a few days or weeks for your body to reach this point.
And it also requires starving your body of carbs, which could make life a bit unpleasant depending on how high your carb intake was pre-keto diet.
Here’s the good news: exogenous ketones can be added to your diet during this transition time to help your body figure out what to do because:
#1: They Help You Avoid the Dreaded Keto Flu for a Smoother Transition
While your body switches from using glucose to ketones, you can make the whole process less painful by supplementing with exogenous ketones.
As we talked about in this guide on the keto flu, adding exogenous ketones to your transition floods your body with the energy it needs (i.e., ketones) to transition to ketosis faster.
In many cases, exogenous ketones can prevent or even eliminate the flu-like symptoms common with this phase of keto.
And that’s not the only time they work well for people.
#2: Exogenous Ketones Give You Life
Just like the regular flu, keto flu and the entire transition can leave you feeling depleted both mentally and physically.
But taking exogenous ketones may help alleviate the situation or prevent this energy crash altogether.
Since these energy molecules are fat-based rather than built on glucose, you’ll have a sustained source of fuel sans carbs to kickstart your day or keep you going longer between meals.
Exogenous ketones are also helpful for getting back into ketosis.
#3: They Help You Reach Ketosis Faster
During your keto journey, you may find certain foods, drinks, or protein bars may actually kick you out of ketosis unintentionally.
And sometimes a low-carb, high fat diet like keto takes a bit of practice and getting used to before you stop having occasional cheat meals.
Instead of undoing all your hard work and calling it quits after one of these carb fests, you can turn to your trusty exogenous ketones to help you get back on track quickly.
Rather than experiencing a tough transition back and forth, EK give you a bit more flexibility in your diet — but not a reason to cheat.
For every 100 people who praise exogenous ketones for these reasons, you may come across a few misinformed folks who believe exogenous ketones and MCT oil prevent you from losing fat on keto.
So let’s unpack this next.
The biggest reason people believe taking exogenous ketones stops fat loss is based on simple, yet flawed, logic:
If you give your body exogenous ketones or something similar like MCT oil, you force your body to use that source of fuel instead of tapping into your own stored body fat for energy.
Further, those against using exogenous ketones claim your body will literally stop making its own ketones because it already has a steady supply of them coming in via EK supplementation.
Obviously you want your body to burn off your fatty problem areas and make its own ketones so this is definitely scary.
But it’s not entirely accurate.
Your body doesn’t wait until everything you’ve eaten is digested before it decides to burn fat.
If this were true, your blood sugar levels would need to plummet so low you’d be knocking on death’s door before you lost a single pound, which we know doesn’t happen.
You literally wouldn’t have enough calories to run important tasks such as breathing, pumping your heart, or sending signals to your brain.
Our very own Alex Cunningham, Head of Partnerships, helps make this easier to understand far better than I could with this simple analogy:
Your body acts like both a refrigerator and a freezer for the energy you get from your diet.
The “food in your fridge” consists of energy substrates, like glucose or ketones, in your blood.
Since your body needs a steady source of energy within reach for all those bodily functions, the protein, carbs, MCTs, ketones, etc., you eat all fill up your fridge first.
When your body needs quick, available energy, it reaches into the fridge, just like most of us do several times a day.
But when your fridge is full, your body naturally moves energy from the fridge to the freezer. This will replenish your energy stores so you have a backup in case you get lost in the desert without food.
The “food in your freezer” is stored energy in the form of adipose tissue or body fat.
Your body will then move energy from the freezer to the fridge when it senses you need access to a quicker source of energy. This means your stored fat gets pushed onto the burning fat line and you start losing weight.
The tricky part here is this freezer-to-fridge process of setting up your stored fat for fuel only happens when your insulin levels dip very low.
While this is good news if you’re on a ketogenic diet, your body’s freezer also shuts off when your fridge is full.
This is a natural response from your body, regardless of taking exogenous ketones.
And it’s not butter, coconut oil, MCTs, or exogenous ketones to blame — it’s insulin.
High insulin levels mean your body will never move energy from your freezer to your fridge. And that means you’ll never burn that stored fat.
The bigger bummer is if your insulin levels are really high, the overflow of fridge food will eventually spill into your freezer and lead to weight gain.
Now, eating and digesting food always affects your insulin levels, but you can’t just not eat.
What’s important here is the degree to which your insulin spikes, and that all depends on the food you eat.
When insulin-spiking foods are added to your fridge, and you repeat this pattern more often than you care to admit, you will prevent your freezer food from moving into the fridge and becoming usable energy.
Again, exogenous ketones will cause insulin to secrete but they are not insulin spiking.
So the takeaway here is:
Your fridge doesn’t need to be completely empty to tell your body to move stored energy from the freezer to your usable energy fridge, but your insulin levels need to be low.
That’s why your focus should be on keeping low sugar levels and periodically going without food (like using intermittent fasting, or fasting overnight for example).
Since your body requires a ton of energy to function, exogenous ketones give it a chance to work through the food in your fridge while also giving you energy.
So now you see the solution to losing weight isn’t avoiding exogenous ketones, but knowing when best to use them.
And the science can help us better learn when those times are.
Exogenous ketones are still fairly new to the science scene, so to speak.
While protein powders have been around for decades and there’s plenty of research to review, exogenous ketones aren’t quite as well-studied yet.
But since more Americans are learning the benefits of low-carbohydrate diets like keto, it won’t be long until more research comes out.
Until then, here’s what the science supports as of publishing this guide:
#1: They Are Helpful for Increasing Ketone Levels
Researchers in one study wanted to see if exogenous ketones could help people reach nutritional ketosis faster and alleviate symptoms of the keto flu.
What they found is exogenous ketone bodies were a “safe and effective way to increase ketone body concentrations[*].”
And higher ketone concentrations mean your body may be further into ketosis, which means you may notice fewer keto flu symptoms during your transition too.
While exogenous ketones can boost your ketone production, they also help tackle this next issue.
#2: They Can Reduce Oxidative Stress & Improve Neuron Energy
Another body of research shows exogenous ketone supplements like beta-hydroxybutyrate, or BHB, work well for replacing glucose as an energy source in your body[*].
Scientists also learned they can help decrease oxidative stress while also boosting neuron energy supplies as well.
And all this happens while EK keep blood sugar regulated, according to the research.
The next study confirms similar findings.
#3: Exogenous Ketones Can Improve Blood Sugar & Help People Reach Ketosis
Researchers discovered exogenous ketone supplements, both ketone esters and ketone salts (which you can learn more about here), increased the level of floating ketones in study participants’ blood[*] .
And that wasn’t all they found.
Their results proved exogenous ketones can help lower blood sugar levels without the side effect of interfering with a person’s own insulin secretion.
This is excellent news for people using a ketogenic diet to lower high blood sugar levels, such as those with type 2 diabetes.
Furthermore, the ketone drinks used during the trials helped people achieve nutritional ketosis without the use of a super restrictive diet.
But having higher blood ketone levels isn’t the only goal here; it’s what happens as a result of this, which I’ll dive into next.
#4: Higher Ketone Levels Helped People Shrink Their Food Intake
Scientists from another study explored how ketone ester drinks, or exogenous ketones, affected people’s appetites and hunger levels[*].
What they found is that, after an hour of consuming exogenous ketones, study participants’ blood ketone levels went from about 0.2 to 3.3 mM
On top of this increase also came lower levels of ghrelin, a hunger hormone that stimulates appetite.
Because of this change, participants reported feeling satiated instead of hungry 1.5 hours after consuming exogenous ketones compared to those in the dextrose-based drink group.
Another big finding here is that glucagon-like peptide (GLP-1) and peptide tyrosine (PYY) both remained significantly lower for 2-4 hours after the exogenous ketone consumption.
GLP-1 is a hormone that stimulates insulin secretion. PYY is an amino acid that binds to important receptors in your brain which send the signal that you’re full after eating.
So exogenous ketones helped people lose weight because it reduced how hungry they felt and how much they actually needed to eat, showing this goes beyond just an increase in blood ketone levels.
And that’s exactly what happened in this last study.
#5: Fat Oxidation is Also Not Hindered in Athletes
When experts wanted to see if exogenous ketones affected fat oxidation in male cyclists, they learned that as long as participants were completing a steady-state exercise, fat burning was greater in the ketone group compared to the control group[*].
Unfortunately, this was not the case with high intensity exercises.
Scientists realized exogenous ketones could actually impair an athlete’s performance because they aren’t made for quick bursts of energy.
Yes, exogenous ketones are metabolized quickly and are used right away, but they’re not going to quickly replenish glycogen stores, which is what someone in high intensity training needs.
Exogenous ketones are better for long-lasting energy so you can power through steady-state sessions.
This is why it’s so important to understand what exogenous ketones can and cannot help you accomplish.
If you’re worried taking exogenous ketones may stop your fat loss efforts, your focus should be on understanding when to take them so you don’t inadvertently gain weight.
But first, you should know ketone supplements like exogenous ketones will not immediately trigger weight loss.
It’s not a switch you can just turn on like that.
Rather, as with all supplements, they should be used in conjunction with an already clean ketogenic diet.
So if you’re trying to practice a “dirty” or “lazy” style of the keto diet and you’re hoping EK will be your free pass to easy ketosis street, you’re going to be in for a bad time.
Exogenous ketones don’t cause weight loss, but they can help kick you into ketosis, and that triggers weight loss.
Even still, as we talked about in this guide, using ketones or even making more of them on your own doesn’t mean you’re going to drop weight or decrease your body fat percentage overnight.
Exogenous ketones are more like a boost to your starting point, helping to get the wheels rolling faster and smoother.
So if you’re making the transition to keto, EK can help facilitate this.
They can also help get you back into ketosis if you’ve had a larger-than-normal carb-heavy meal.
Exogenous ketones are even helpful for increasing energy levels when you’re weaning yourself off fast-acting carbs too.
All these perks combined will help you feel good on keto so you can actually stick with it long enough to reap all the positive health benefits.
So to keep life easy, follow this schedule of best times to use exogenous ketones:
- Before or after a workout
- When you wake up in the AM
- After carb-intense meals
- To suppress your hunger during a fast or on an empty stomach
- To enhance ketone production
It’s also smart to regularly test your blood ketone levels when using exogenous ketones to see how they affect you specifically.
And you should move beyond basic urine test strips to do this and instead use a blood sugar meter to accurately assess your ketone production.
As we talked about in this podcast episode, the goal is not just having high levels of ketones.
It’s about finding the sweet spot that works for your body; the point where you’re in ketosis and it feels good for you, like a “keto high” (which is similar to a runner’s high).
You’ll never know where your sweet spot is if you’re not effectively tracking how exogenous ketones affect you.
While it may take a bit more effort, the long-term rewards will be worth it when you eventually do make the switch from glucose to burning ketones.
Myth Busted: Exogenous Ketones Will Not Prevent You From Losing Fat (Just the Opposite Happens)
Now that you know the science behind what really happens when you take exogenous ketones, you can finally put this false myth to rest.
As you saw in this guide, exogenous ketones pack a number of different health benefits and can be a successful tool for reaching ketosis faster.
When you add them to a clean ketogenic diet and use them when they’re best suited, they won’t prevent you from losing weight and tapping into your fat stores.
They’ll actually help you speed up the process.