Do Artificial Sweeteners cause problems on a Ketogenic Diet?

There’s mixed opinions regarding artificial sweeteners in the ketogenic world, with some cautioning against their use. One common concern is that they can cause a rise in blood insulin levels, which is something we are specifically trying to avoid by restricting carbohydrates.

I’ve been eating low carb / keto for about 19 years now, and lost, and kept off, 90 pounds. My wife has been even more successful over a shorter time period, losing 175 pounds. Both of us use artificial sweeteners, either in the form of diet soda or adding it to foods we make (and in her case keto friendly things she bakes).

Were we just lucky? I wanted to see whether there was any scientific evidence supporting the view that they raise insulin levels. A Google search turned up numerous pages advising against using artificial sweeteners. Most were unsourced, but quite a few did reference another website or a book, for example Dr. Jason Fung’s The Obesity Code, so I decided to start there. From chapter 15:

The important question is this: Do artificial sweeteners increase insulin levels? Sucralose(13) raises insulin by 20 percent, despite the fact that it contains to calories and no sugar. This insulin-raising effect has also been shown for other artificial sweeteners, including the “natural” sweetener stevia. Despite having a minimum effect on blood sugars, both aspartame and stevia raised insulin levels higher even than table sugar.(14) Artificial sweeteners that raise insulin should be expected to be harmful, not beneficial. Artificial sweeteners may decrease calories and sugar, but not insulin. Yet it is insulin that drives weight gain and diabetes.

Jason Fung, The Obesity Code, Chapter 15, page 172

Next, I read these two studies myself, to see if they really justified the concerns over use of these sweeteners, specifically do they cause a rise in blood insulin levels for people eating a low carb / ketogenic diet. Here are the papers in question, along with links to the papers themselves. I’d suggest reading them before moving on to my interpretation of the studies:

13: Pepino et al: Sucralose Affects Glycemic and Hormonal Responses to an Oral Glucose Load. Diabetes Care 2013 Sep; 36(9): 2530–2535.

14: Anton et al: Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels. Appetite. 2010 Aug; 55(1): 37–43.

In the first study, Sucralose Affects Glycemic and Hormonal Responses to an Oral Glucose Load, seventeen obese test subjects drank either sucralose or regular water, and then underwent a standard five hour oral glucose tolerance test. This test measures the subject’s glucose level after fasting (as a baseline) and then after drinking a glucose solution (essentially sugar water), and was historically the standard test for diagnosing diabetes. Their blood glucose level is measured over five hours. In subjects without diabetes, their blood glucose level rises and falls quickly, in those with diabetes or an impaired glucose tolerance the blood glucose levels rise higher, and remain elevated for a longer time period. In this study, the subject’s blood insulin level was also measured, in addition to blood glucose.

The first graph, below, shows the blood glucose level of the subjects during the experiment as two lines, one for those who first drank water, as well as for those who first drank sucralose.

Up until time 0, when the oral glucose was administered, the blood glucose level was the same for both sets of test subjects. After administering the oral dose, the blood glucose levels went up as you would expect, although the peak value was higher for those who had sucralose first (more about this later!)

Next we have a graph of their blood insulin levels:

Again both graphs overlap before administering the glucose, implying that the sucralose did not cause a spike in blood insulin levels. As with the peak blood glucose level, the peak insulin level was higher for those who had sucralose prior to glucose. In both cases, think of the sucralose as having a multiplier effect on the later dose of glucose. What is going on here?

My suspicion is that the sweet taste of sucralose is priming the body to get ready digest food. Think back to Pavlov’s famous experiment with dogs, where they started to salivate when the bell was rung, the saliva contains enzymes that help break down food. If there’s an larger supply of these enzymes and other compounds available, it could facilitate faster absorption of the glucose. And indeed there is a phenomena known as cephalic  phase insulin response (CPIR) which could be at play here, which I will also address further down.

If you’re eating a ketogenic or low carb diet, this would not be an issue, since you’re not eating carbohydrates, not more than very small amounts anyway. Remember how I considered the sucralose as having a multiplier effect on the blood glucose and insulin response? If you’re not eating carbohydrates, you’re not going to have a response. And anything multiplied by zero is still zero. So this isn’t going to affect you.

But if you’re eating the SAD (Standard American Diet) full of sugars and other carbohydrates, it’s quite plausible that drinking a diet soda along with your giant fries and burger could spike your insulin levels higher than if you just drank a glass of water. Of course the burger and fries alone would do that, but the diet soda might make it even worse. You can also argue that drinking a sugar filled non-diet soda would be just as bad or likely even worse due to its high sugar content.

But the key takeaway point for us, again, is that on a keto diet, it’s a non issue, as we are not eating a sugar or starch filled meal along with our diet soda. For example, if you eat a few eggs and some cheese, let’s say with 5g of carbohydrates, then a 20% increase in insulin levels would make that meal equivalent to eating 6g of carbs instead. It’s certainly something to factor into your daily meal planning, but is it significant? Further down I discuss CPIR, including a study that suggests other tastes may also trigger an insulin response prior to eating any carbohydrates, even those not from sweeteners. You may get the increase in insulin levels from eating virtually anything.

The second study, Effects of stevia, aspartame, and sucrose on food intake, satiety, and postprandial glucose and insulin levels, is used to support the claim that aspartame and stevia raise insulin levels, and indeed raise them higher even than table sugar. Let’s take a look at the study.

In the study, 31 individuals, 12 of whom were obese, participated in an experiment to see if substituting low calorie sweeteners for sugar would help with weight management. Stevia and aspartame were the low calorie sweeteners used, in addition to sucrose (regular sugar). The purpose of the experiment was not to see if these sweeteners adversely affected blood insulin levels, although blood insulin levels measurements taken during the trials have been used to support that claim.

The subjects fasted for 12 hours, arrived at the test center, and were fed a 469 kcal breakfast of cereal, milk, toast with butter, and orange juice. Then they were fed a 400g “preload” of tea and crackers with cream cheese sweetened with either stevia, aspartame, or sucrose 20 minutes before their test lunch or dinner meals.

The lunch meal was sandwiches, potato chips, and cookies. The dinner meal was a “self-selected buffet-type meal” (the details are in the paper, it too was just as high carb as lunch). So both meals were SAD (Standard American Diet), not keto. The subjects were allowed to eat as little or much of each meal as they liked, and reported their hunger and satiety levels. Again, recall the purpose of this experiment was not to see the effect of low calorie sweeteners on blood insulin levels, but whether or not they could be used in a diet to limit overall food/calorie consumption. I won’t dwell too much on the experiment results since they’re not relevant to the insulin effects other than to note that “Reported hunger and satiety levels did not differ by condition at any time point” even though they ate “significantly fewer kcal”.

The paper concludes “In conclusion, participants did not compensate by eating more at either their lunch or dinner meal and reported similar levels of satiety when they consumed lower calorie preloads containing stevia or aspartame than when they consumed higher calorie preloads containing sucrose.” Sounds to me like it was a success. Low calorie sweeteners can be helpful for people trying to diet and reduce weight. And these subjects were not even eating a low carb or keotgenic diet!

So back to the original ketogenic diet related claim, “Despite having a minimum effect on blood sugars, both aspartame and stevia raised insulin levels higher even than table sugar” and therefore should not be consumed on a low carb / keotgenic diet.

Blood insulin levels were measured before the “preload” meal, after it, as well as before and after the lunch meal. Figure 3 from the paper shows these blood insulin levels:

In all three cases (Stevia and aspartame, as well as regular sugar/sucrose) blood insulin levels went up after the preload. But wait, what was in this preload? Crackers with cream cheese! They did not consume just aspartame or stevia, they consumed it along with crackers.

The cracker and cream cheese meal with stevia and aspartame was reported as 290 kcal, unfortunately the paper does not specify the nutritional information for it, so we don’t know the sugar content. Crackers have a very high glycemic index, typically in the range of 67-81. Foods typically affect blood sugar levels by their glycemic index as a percentage relative to pure glucose – a large amount in this case.

Therefore, it’s not surprising the subjects had a blood insulin response. But don’t blame the aspartame or stevia for what the crackers did. At the end of the two hour measurement period, the insulin levels were approximately the same for all three cases, with the two low calorie sweeteners indeed slightly higher. But this was after eating a non keotgenic / high carb / SAD lunch. I find it difficult to believe this is relevant for someone eating keto.

As you can see in Figure 2 from the paper, aspartame and stevia did indeed have less of an effect on blood sugars than plain sugar/sucrose:

This is to be expected, since in those cases the subjects consumed less carbohydrate (they did not eat the sugar in addition to the crackers), and less insulin needed to be released by their body to deal with it.

It is worth repeating again, in this experiment the subjects did not consume just aspartame or stevia. They ate crackers and cream cheese, with either of those sweeteners or with regular sugar. That is why their insulin level went up. This study does not confirm that aspartame or stevia causes blood insulin levels to increase. It does however confirm that use of low calorie sweeteners does not cause an increase in calorie consumption, suggesting that they can be appropriate for a keto lifestyle.

Earlier I mentioned cephalic  phase insulin response (CPIR), which is the release of insulin prior to an increase in the blood sugar level. One paper which presents human experimental results is Just et al: Cephalic phase insulin release in healthy humans after taste stimulation? Appetite. 2008 Nov;51(3):622-7

Two studies were performed, a pilot with five subjects and a second with 20 subjects. In each study the subjects tasted (swished in their mouths but did not swallow) a specific taste while their blood glucose and insulin levels were measured: before the taste test and 3, 5, 7 and 10 minutes after.

In the pilot study, the subjects tasted starch, quinine (bitter taste), citric acid (sour), distilled water, MSG (umami) NaCl (table salt). The second study had two sweet tastes, sucrose (table sugar) as well as saccharine.

The glucose readings were relatively stable for all of the readings, while the insulin levels had more noticeable changes. (See Table 1 in the study) Insulin levels increased slightly for the sucrose and saccharine tests. But they also increased for quinine, starch, and even the plain distilled water (the latter two dismissed in the paper due to “outliers”). Curiously the insulin readings (both before and after tasting) for the salty taste were all significantly lower than for the other tastes, about 5.0 vs 8.5. Also the sour taste run had somewhat higher values, 11.0 vs 8.5. From the paper “The taste solutions were given in a randomized order, each solution was presented on a separate day.” This suggests to me that there could have been an offset error in the insulin readings for those two days. I’m not sure if it affects the validity of the results, but it is suspicious.

In addition, as an engineer with a background in process control, the insulin readings look extremely “noisy”to me. In addition to the large standard deviations in the values in Table 1, the baseline measurements where the fasting insulin level was measured every 2 minutes shows a continuously increasing variation in readings between subjects. Is this a measurement error, or because human insulin levels are continuously varying, perhaps to control blood glucose? How much of this noise is being added to any actual variations driven by the tastes?

While the paper focused on the effects of sucrose and saccharine, other tastes also produced an effect. Does the body only release a small amount of insulin when sweet is tasted, or does this occur for multiple tastes? All tastes? If so, it doesn’t matter what you eat, you will have a small increase in your blood insulin level, even if it’s not a sweetener. Regardless, the changes in insulin levels in all cases was small, in the case of saccharine around 11%. Remember from the earlier oral glucose experiment, the change was significantly larger, the 75g glucose load caused an approximately 1000% increase in insulin levels. This doesn’t proscribe the use of low calorie sweeteners by individuals on a ketogenic diet who are trying to control their blood insulin levels.

Control systems (sorry, I have my engineer hat on again) use a mix of feedback and feedforward for regulation. It’s probably not surprising that the body slightly increases insulin levels in anticipation of blood glucose levels possibly rising after eating, in addition to any releasing insulin when glucose levels do rise. In pre modern times, there were few if any sources of food that contained a large amount of sugar that would dramatically raise insulin levels, how often did our ancestors successfully raid a honeybee hive? The small bump in insulin would be sufficient for a few wild berries, root vegetables, etc. The insulin feedforward system may be coarse enough to respond to virtually any taste / food source, not just sweet.

My conclusion: The studies cited supporting the belief that artificial sweeteners significantly raise insulin levels on a keto diet don’t actually show that.

Authentic Buffalo Chicken Wings

I’m a big fan of chicken wings, one of the perfect keto foods. I started eating them back in the mid 1970s when I lived in the Buffalo area, well before they became popular nationwide. Over the decades I’ve continuously tweaked my method of making wings, trying to make them taste as authentic as possible to what I remember. This recipe optimizes taste over ease of preparation. It’s not a quick “throw wings in deep fryer for ten minutes slather with sauce then eat right way” recipe. Although you can certainly make them that way if you don’t have the time. My goal was to duplicate the taste of wings from my childhood. I think I got pretty close.

Ingredients and required tools:

You’ll obviously need some chicken wings. I prefer using fresh vs bagged frozen and already cut wings.

Next you’ll a deep fryer to cook the wings. Don’t try to do it on the stovetop in a pot, it’s almost impossible to accurately control the oil temperature. I used to use one of the fancy countertop deep fryers with a basket, but got tired of how difficult they are to clean. So I’ve switched to the good old Fry Daddy. We actually got three of the Presto Big Kettle Multi-Cooker & Steamers, which is the largest version. It seems to only be sold at WalMart.

Why three? Well, we also cook some other deep fried foods for the kids, but I wanted one that would only be used for wings, so the oil would last longer. Having three means there is a spare, so we can filter the oil by directly pouring it through a strainer (optionally with cheesecloth) into the third fryer, and not dirty up a bowl as a temporary vessel to hold the oil. Then clean the old fryer, and put it into rotation for next time. This style fryer is super easy to clean, you can even do it in the sink, it’s waterproof.

Next choice is the oil for the fryer. Personally I prefer peanut oil. It’s a little more expensive than regular vegetable oil, but lasts longer, before the oil breaks down and needs to be replaced. It’s also a healthier option. I’ve not tried using lard, which would be an even healthier option, but that should work as well.

You’ll also need butter and Frank’s Red Hot sauce (the original / authentic sauce to use) and optionally some Tabasco sauce to increase the heat, plus a bowl to coat the wings with sauce. I find a plastic bowl with snap on lid works best.


Pour your oil into the deep fryer and get it warming up. Be sure to set the fryer temperature at or below the smoke point of the oil you’re using. For peanut oil I use 400F. Also set your oven to 150F, you will be stashing the fried wings here during the cooking process.

Separate the wings at each joint using either kitchen shears or a knife. Each wing has three parts: the drumette, the flat, and the tip. Tips don’t have enough meat on them to be worth frying, but you can save them for making stocks.

Deep fry the wings in small batches. Don’t overload the deep fryer, or the oil temperature will drop too low! That will result in soggy yucky wings, and more of the cooking oil may enter the food. Not what you want. I cook up to ten wing pieces at a time, in a smaller fryer you may have to fry fewer at a time.

I find it takes about 8-9 minutes to fry, you will know they are cooked when they float to the top of the oil. You can always take one out and check it with an instant read thermometer to make sure it is 165F in the center.

Place the cooked wings on a rack over paper towels, or directly on the paper towels themselves on a plate (yes, I know, everyone says your fried food will be greasy if you do this, I find if you don’t put too many on at a time, it is fine). Place into the warm oven.

Continue to fry any additional batches. When you’re done, keep the wings in the warm oven for 30 to 560 minutes, this helps make the skin more crispy, without continuing to cook the inside. Don’t worry, at 150F you are above the minimum 140F temperature to stay out of the “danger zone”.

Now make your sauce. The classic sauce is made with equal parts of melted butter (I use the microwave) and Frank’s Red Hot Sauce. This is the typical heat level. I find that 2 tablespoons each of butter and hot sauce is enough to coat 20 wings. If you want your wings very mild, you could use more butter / less hot sauce. If you want to make them spicier, add Tabasco sauce. This is something you will need to adjust on a personal basis. I mix the butter and hot sauce into an emulsion using a small battery powered mixer/frother in a measuring cup. I do not add any salt to the sauce, there is enough in the butter and hot sauce.

Remove the wings from the warm oven (but keep it on!) and place into the plastic bowl, pour on the hot sauce, put on the lid, and gently shake to coat the wings. Then remove the wings from the bowl and put on a plate (not plastic!) and put back into the 150F oven for another 30-60 minutes. I find this final step is key to getting the authentic wing taste. Perhaps it duplicates the tine the wings sat in a bucket on the way home from the wing/pizza shop?

Now you’re ready to eat. I like a light sprinkle of salt on the wings (notice I don’t add any to the hot sauce itself), but I like my foods on the salty side, so you may want to try them without salt first. Wings are often eaten with celery which is generally OK on a ketogenic diet in reasonable quantities. Blue cheese dressing as dip is also popular, I don’t use it myself, but check the label, many brands are relatively low in carbs, but some may not be.

Easy Pan Seared Strip Steak

Steak is an excellent keto meal. And you don’t need a grill to make the perfect steak. I’ll show you how to do with with your oven and frying pan.

This method works perfectly with any steak. I’m using a NY Strip, it works equally well with a Ribeye or other cut. You’ll need some butter to sear the steak, and I’m going to use the pan drippings to sauté some mushrooms (completely optional, of course)

We’ll start by cooking the steak in a slow oven, I use 200F (100C). This allows the steak to evenly reach the desired temperature, so most of it is perfect medium rare, with little gray area. A oven safe temperature probe is highly recommended, to make sure you don’t shoot past the goal temperature of 100F (38C).

Place the streak on a roasting rack and insert the temperature probe, getting the tip into roughly the center of the steak. Put it in your oven and set the alert temperature to 100F. I find this takes about 45 minutes, but it will vary with the size/shape of your steak, how warm it was when it came out of the fridge, as well as how hot your oven actually is (many ovens are way off temperature).

The steak has reached 100F, so we’ll take it out of the oven and move on to the next step, searing it. I like to turn off the oven and keep the door open for a few minutes at this point, so it is warm enough to keep the steak warm after searing, but not hot enough to continue cooking it.

Melt 2 tablespoons of butter (I love KerryGold brand) on medium high heat in a stainless steel frying pan. Non stick pans are not recommended, as you won’t get nice sear. You want the pan to be hot enough to get nice browning, but not burnt.

Sear on one side until golden brown and delicious (3 to 5 minutes), then flip and do the other side. When done, remove and put in your slightly warm oven to keep warm, while we make some sautéed mushrooms.

To keep things easy, I’m using canned mushrooms. Pour some of the liquid from the mushrooms in the pan to deglaze it, then add the mushrooms. Maybe some garlic after the liquid has reduced. There should be plenty of fat left in the pan from the butter and steak, but you could add more if needed. Stir occasionally for 5 to 10 minutes.


Recipe: Just Cheese Crackers

KODAK Digital Still Camera

This is a quick and easy way to have a salty and crunchy snack food to replace chips or pretzels. They keep well and can be modified based on what type of cheese you use and can have spices added to them.


  • 3 slices of deli sliced cheese, any type (I used white cheddar)
  • spices or flavorings to sprinkle on top (optional)


Preheat oven to 250 deg F. and line a sheet pan with parchment paper.

Take each slice of cheese and cut it into 4 equal pieces. Place cheese squares on the parchment with space between them so they don’t melt together when baking. Sprinkle with seasonings if you are using them, and don’t forget to add the spices to your total carbs.

Place in the oven for 40 minutes. Remove the cheese from the oven and allow to cool a few minutes, long enough to be able to flip them over on the sheet pan. Replace the pan in the oven for another 15 – 20 minutes.

Remove from oven and allow to cool, then place the squares on a piece of paper towel to blot the grease from the crackers. Cover with another paper towel and blot gently. The crackers can be stored in a plastic bag after fully cooled.

12 crackers has 195 calories, 0 carbs, 13 g Fat, and 17 g Protein.

What should I eat on a Ketogenic diet?

This is the first question most people ask when starting a Ketogenic diet, so here is a good beginners list of things to consider at the store.

Protein Sources

  • Beef
  • Chicken
  • Pork
  • Turkey
  • Fish
  • Shellfish
  • Lamb
  • Bacon, Pepperoni, Lunch Meat, Hot Dogs, Sausage, Pork Roll, and other processed meats *

*Watch labels with these items, as carbohydrate count can vary.


  • Butter or ghee
  • Heavy cream
  • Eggs
  • Cheese, both hard and soft
  • Full fat versions of sour cream, creme fraiche, cream cheese,cottage cheese, mascarpone, ricotta, and plain greek yogurt

Vegetables and Fruits

All vegetables and fruits are going to have some carbohydrates in them, so it is best to keep track of how much you eat and how many net carbs are in them. Here’s are commonly eaten items that will fit into your carbohydrate limit nicely.

  • Lettuce, any type
  • Leafy greens, like spinach, kale, collard greens, etc.
  • Eggplant
  • Avocados
  • Asparagus
  • Cabbage
  • Broccoli
  • Brussel sprouts
  • Cauliflower
  • Zucchini
  • Yellow squash
  • Green beans
  • Celery
  • Mushrooms
  • Tomatoes
  • Cucumber
  • Turnips
  • Radishes
  • Herbs
  • Raspberries, blueberries, and strawberries in moderation

Other Items

  • Nuts (always check the label for net carbs)
  • Coconut oil
  • Peanut oil
  • Olive oil
  • Seeds (flax, chia, pumpkin, sunflower)
  • Beef jerky or meat sticks (check labels, some have a lot of carbs)
  • Almond meal or coconut flour
  • Low carb bars or snacks, usually found in the diet aisle
  • Sugar free sauces (ketchup, BBQ sauce, mustard, mayo, etc.)
  • Coffee or tea
  • 0 carb sweeteners

This is by no means an exhaustive list of foods, and as you learn to read labels you’ll find many others that work fine for a ketogenic diet. But, as a starting point, it should get you on the right track! Now, go get your keto on!

What is a Ketogenic Diet?

Everyone recently has their own ideas about what constitutes a Ketogenic Diet. There are rules galore, and every group of people you talk to will have different ideas about what rules are important and what are not. It’s confusing, but it doesn’t have to be.

A Ketogenic diet is, in general, a diet which allows you to burn fat for energy and keeps your insulin and glucose levels low. People often use 20 grams of total carbohydrates as their daily goal, but others will use a calculation of less than 5% of your daily calories coming from carbohydrates. If you use a percentage, you’ll need to know your daily caloric goal and work off of that number to see how many grams of carbs you’ll need. I find that keeping net carbs under 20 grams per day works just fine for most people, and it’s an easy number to calculate in your head if you don’t like tracking everything.

If you keep your carbohydrates this low you are eating a Ketogenic diet. This is the ONLY strict rule you need to follow. What you choose to eat to meet this goal is ultimately up to you. You are free to make your own choices about what is working or not working in your diet. You can track calories or not. You can use artificial sweeteners if they work for you. You can eat eggs every day, or avoid them like the plague. It’s totally up to you to decide.

This is not to say there aren’t things that can be helpful to think about when eating a Ketogenic diet. I will be covering some of those things in future posts, so stay tuned!

Recipe: Easy Cheesy Bread

KODAK Digital Still Camera

This is an easy recipe that makes Keto buns or bread to use for burgers and sandwiches.  They keep well in the refrigerator if you make extra, and they are super yummy as a snack by themselves.  


4 oz. shredded cheese (I use Mexican 4 Cheese Blend)
2 oz. grated Parmesan cheese
2 tsp. coconut flour
2 lg. eggs
1/4 tsp. garlic powder (optional)


Preheat oven to 375 deg F.

In a bowl, weigh out your cheeses. Add in the coconut flour and garlic powder (if you are using it) and mix together to distribute the flour through the cheese mixture. Add in the eggs and mix well to combine.

On a baking sheet lined with parchment paper make 4 equal piles of the cheese/egg mixture and make them a general round shape. They don’t need to be perfect, as the cheese will spread. Bake at 375 deg F for 15-18 minutes until they look golden brown (and delicious). Cool on the pan and eat or store in the refrigerator. Can be reheated by toasting or warming in the oven.

One bun is 200 calories, 1.4 g Net Carbs, 15 g Fat, and 16 g protein.