All You Need to Know About Carbs on a Low-Carb Ketogenic Diet

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When it comes to ideal carbs intake, I've discussed it in my post here: How Many Carbs per Day on Low-Carb Ketogenic Diet? However, daily carbs intake is not the only aspect you should focus on.

Does our body need carbs?

It's a common misconception that our body, especially our brain needs carbs. In fact, the brain can either use glucose or ketones. When you restrict the intake of carbohydrates, your body will switch to using ketone bodies instead of using glucose. Not only that, ketones are a better fuel for our body and brain than glucose, even for highly active individuals. Once you get keto-adapted (3-4 weeks), you will experience improved energy levels. Although a small amount of glucose is still needed, our body can produce glucose on demand via gluconeogenesis.

Dr Volek and Dr Phinney, The Art and Science of Low Carbohydrate Performance (2012):
"Ketone bodies are an important lipid-based fuel, especially for the brain, when dietary carbohydrates are restricted."

It has been estimated that about 200 grams of glucose can be generated daily just from protein (Dr Briffa, Escape the Diet Trap, 2012). Our body needs some glucose (e.g. for the thyroid health) but according to Dr Volek, it's a very small amount. As I said in my post here, there is no need for everybody to follow a very low-carb / "zero-carb" diet and you may need to adjust the level of carbs to fit your needs.

Types of carbs in ketogenic diets

Generally, you should avoid any sugary or starchy foods. The best measure to represent "good" and "bad" carbohydrates is their Glycemic Load (GL), which measures how much insulin will be released by your body for a given food measured in standard portions. This is different to Glycemic Index (GI), which doesn't take the serving size into account. As a result, some foods with high GI could have low GL. Therefore, Glycemic Load is recommended as the best measure for carbs. Most of your carbs should come from non-starchy vegetables (leafy greens, cruciferous vegetables such as broccoli, zucchini, etc.) and nuts.

One of the exceptions where high GI/GL food is recommended is on Targeted Ketogenic Diet (TKD).

According to Lyle McDonald in his book "The Ketogenic Diet":

"Although experimentation is encouraged, most individuals find that 25-50 grams of carbohydrates taken thirty minutes before a workout enhance performance. The type of carbohydrate consumed pre-workout is not critical and individuals are encouraged to experiment with different types of carbs. Most seem to prefer easily digestible carbohydrates, either liquids or high Glycemic Index (GI) candies to avoid problems with stomach upset during training. A wide variety of foods have been used prior to workouts: glucose polymers, Sweet Tarts, bagels, and food bars; all result in improved performance."

Total Carbs vs Net Carbs

A frequent question amongst low-carb dieters is: Should fiber be included when counting carbs?

Let's look at the evidence: Although some soluble fiber may be absorbed, humans don't have the enzymes that could digest most fiber and derive any calories from it. As a result, fiber does not significantly affect blood sugar and ketosis. In general, you can either aim for 20-25 grams of net carbs or ~ 50 grams of total carbs as recommended by Dr. Steve Phinney and Dr. Jeff Volek.

When fiber is not taken into account, the derived carbohydrate values are known as net carbs. Using net carbs reduces the impact of high-fiber foods (vegetables, nuts, etc.) and you can include them in your diet. This turns out to be an argument against those that criticize low-carb diets for the lack of fiber. It's important to stress that fiber doesn't negate carbs - it's simply not counted; so mixing flax meal into a bowl of pasta won't work! You can read more about total vs net carbs in my post here.

Here is the catch: When it comes to food labeling, in countries like US and Canada, carbohydrate values also include fiber (i.e. total carbs). These countries use the indirect method of calculating carbs which means that carbs are calculated "by difference" after they measure protein, fat, water and ash per 100 grams. To get the value for net carbs, you will need to subtract fiber from total carbs. However, this food labeling doesn't apply universally. In other places like Europe, Australia and Oceania, it's common to exclude fiber. They use the direct method of calculating carbs, and therefore "carbs" on food labels refer to net carbs. Keep in mind it doesn't matter where a certain product is sold but where it's imported from.

All You Need to Know About Carbs on a Low-Carb Ketogenic Diet

How can you be absolutely certain about the number of net carbs? Here are 3 simple rules to follow:

  • total carbs can never be lower than fiber
  • total carbs minus fiber can never be less than sugar (net carbs = sugar + lactose + other sugars)
  • total kcal = calories from fat + calories from protein + calories from carbs (without fiber)

Thankfully, you don't need to do the math yourself. You can use this Hidden Carbs Calculator to find out.

How Many Carbs Per Meal to Avoid Insulin Spikes?

We are all different and what is too much for you, may not be for someone else. The best way to find out is to monitor how you feel. If you feel tired and sleepy after a meal, you likely had too many carbs and are experiencing an insulin spike. The trouble is that with elevated blood sugar, you will soon become hungry and eat more than usual. Unless you eat extra carbs as part of TKD, you should avoid eating too many carbs. Some people can't eat more than 10 grams of net carbs per meal, while others don't experience any significant insulin spikes at a much higher level such as 50 grams of net carbs.

All You Need to Know About Carbs on a Low-Carb Ketogenic Diet

My personal carb tolerance is quite high but I avoid using certain foods such as tropical fruit and even some low-carb sweeteners like Xylitol. Apart from potentially causing terrible digestive issues, Xylitol is not zero-carb and may affect your blood sugar. I prefer to use Erythritol or stevia which have very few carbs. Having said that, not all people have issues with Xylitol. For more about sweeteners, check out my post Complete Guide to Sweeteners on a low-carb Ketogenic Diet.

"Zero-carb" Products and Marketing Tricks

Some brands of low-carb foods use misleading labels such as, "carbs-free", "low-carb" or "zero-carb". You have to be extra careful when buying products like that. Apart from pure fat and meat, there is nothing truly zero-carb. It's not a secret that Atkins products and many other use effective and deceptive marketing tricks. Their products often contain sorbitol, maltitol and other types of sugar alcohols that are associated with insulin spikes and raised blood sugar levels. The paradox here is that even Dr. Atkins in his 1999 edition of "New Diet Revolution", said that "Sweeteners such as sorbitol, mannitol and other hexitols (sugar alcohols) are not allowed."

All You Need to Know About Carbs on a Low-Carb Ketogenic Diet

According to Dr. Andreas Eenfeldt (also known as Diet Doctor), there are more than just Atkins Fairy Tale Cookies to avoid: Julian's Bakery Bread and Dreamfields Low-carb Pasta can be added to the list.

In summary, make sure you always opt for real unprocessed food and avoid prepared meals full of additives and deceptive labelling.

Carbs Before or After Exercise?

If you are physically active, you can try TKD (Targeted Ketogenic Diet) and have small snacks before your workouts. If you are doing lower intensity activity such as walking or light cycling, you won’t probably need any pre-workout meal. While carbs (or even coconut oil) before exercise can improve your performance, carbs after exercise have a different effect.

Whether or not you eat carbs after exercise depends on your goals:

  • If you want to lose fat, you should avoid post-workout carbs. You probably have enough fat tissue for energy that can be converted into muscles. Losing fat may be difficult even on a low-carb ketogenic diet. Check out my post here: Not Losing Weight on Low-Carb Ketogenic Diet? Don’t Give Up and Read Further

  • If you want to maintain your weight, you won't need any post-workout carbs unless you did a really intense exercise for an extended period of time. All You Need to Know About Carbs on a Low-Carb Ketogenic Diet

  • If you want to gain weight (muscles) or you are a bodybuilder, you can either follow a standard keto diet or add post-workout carbs. You can try pumpkin, sweet potato, root vegetables, berries, banana, etc. You can find more about CKD (Cyclic Ketogenic Diet) here.

The effect of eating carbs strategically is simple. Any carbs consumed raise your insulin level which normally leads to increased energy levels or storing fat. Here is a short video in which Jennifer Elliott, an Australian dietitian, explains such effects of insulin. However, post-workout carbs may have an anabolic effect and stimulate muscle growth (depending on the workout and intensity). This doesn't mean that you need to eat carbs if you want to gain muscles. Unless you aim for a significant muscle gain, post-workout carbs are not needed.

You can read even more about carbs and exercise nutrition in this post: Ketogenic Nutrition and Exercise: Carbs

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Martina Slajerova
Creator of KetoDietApp.com

Martina Slajerova

I changed the way I ate in 2011, when I was diagnosed with Hashimoto’s, an autoimmune disease that affects the thyroid. I had no energy, and I found it more and more difficult to maintain a healthy weight.

That’s when I decided to quit sugar, grains, and processed foods, and to start following a whole-foods-based ketogenic approach to food.

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Comments (78)

Good article though inconclusive in the end.
One thing though. Xyletol has no actual carbs and has no impact on insulin. NONE,, zero. I actually determined this by blood ketone measurements for up to 12 hours post consumption on several clients and myself. It's a sugar alcohol. Which isn't equal to carbs. So, 0 carbs.
But there may be a caveat.
Digestively speaking it's a matter of the body getting used to it. It's by far the best sugar substitute for keto. Unless it's mixed with maltodextrin or other filler which, by the way , erythrol usually is. Erythrol is also a sugar alcohol and has  near identical impact on digestion as Xyletol as any other sugar alcohol does. Issues with SAs and insulin is most often in purity..
So maybe, when estimating how sweeteners impact insulin, it would be better to shy away from making broad statements especially when they're likely not applicable to all people.
For example many people get migraines from too much stevia. I stumbled upon this in a personal experience and then researched furher.
Many swear by heart they get kicked out of ketosis by it. I don't for example.
It doesn't mean everyone experiences the same problem and innacurate information steers people in wrong directions. Much is up to self testing.
Last night I had two tablespoons of xyletol in an avocado-walnuts-cocoa shake. My blood ketone levels were much higher after consuming it than before. And this morning even higher.

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Thank you for you insights. GI of Xylitol is 13, as compared to Erythritol which is 0 so it is not true that Xylitol has no effect on blood sugar. It may not affect you in the amounts you are using it and it is a good low-carb option but not the best option. This is definitely down to individual tolerance but based on my experience, Xylitol is more common to cause digestive issues. That is the reason I personally avoid it - or use it in small amounts. I don't have the same experience with Erythritol. As explained in this post, others are absolutely fine with Xylitol and can use it without any issues. The impact of sweeteners is explained here: Complete Guide To Sweeteners on a Low-carb Ketogenic Diet
As another example, apart from a few people (including my partner), IMOs affect most people in terms of raised blood sugar (including me) and are not a suitable low-carb sweetener. I agree that self testing is the best approach when choosing the right sweetener. Better safe than sorry, especially with sweeteners.
Lastly, rather than measuring ketones, it's better to measure blood sugar when assessing the effect of foods. Blood ketone levels show how much you have in your "fuel tank" rather than showing immediate effects of foods you've consumed. Blood sugar levels do not always correlate with ketones - not in the same way: Product Review and Giveaway: Sukrin
As you can see in the chart from the link above, while I experienced a significant blood sugar spike 30 minutes after consuming IMOs (Test 1), I barely saw any effect in blood ketones. There was a change but it was relatively insignificant as it's normal to see a drop in ketone levels after (most) meals.

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So I'm confused as to why total carbohydrates matter at all in the keto diet?  Why do I have to keep total carbs at 50 with net carbs at 20-25?  If I'm eating really high fiber foods like vegetables and my total carb is 60 but my net is 25, does it matter?  

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Hi Valerie, you don't have to count fibre - I hope this helps: Total Carbs or Net Carbs: What Really Counts?

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Hello! I love all your post! So much info! I was wandering about potassium and carbs, even on days I eat tons of spinach, cauliflower, raw cacao and pork I can't reach more than 3500mg (with 21g of net carbs), when the amount recommended is 4700. In my country we don't have access to potassium supplements so is even more complicated. How can I eat more potassium and don't go to much up on carbs? (I don't eat sea food or avocado's can't tolerate). I have access to Mccormick salt substitute, but it doesn't say the amount of potassium so I don't know how much to use to make an electrolyte drink. Can someone help me?

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I am just starting out on the keto diet.  At first I thought I understood how to count my carbs... but I am getting myself confused.  Easy I ate a salad consisting of 4 oz chicken breast, 6 oz green leaf lettuce, 6 oz. broccoli,1 oz cream cheese and full fat ranch dressing...
I am coming up with 28 g protein...8 g carbs...and whatever the 2 Tbsp of ranch would be... My question is that on the carb side of things it gives the net carbs and the protein for a certain vegetable... Do I count the protein of the vegetable and add it to my meat protein??  I am so confused..

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You said: "Some people can't eat more than 10 grams of net carbs per meal, while others don't experience any significant insulin spikes at a much higher level such as 50 grams of net carbs." Wondering why you're using grams. Isn't the GI of the carb what drives the size of the insulin spike? Thanks!

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So is it just the sugars that I count as Net carbs if I'm in Australia which is based on the UK breakdown of carbs in food labelling

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Dear US food people, total is always higher than net.  Net = total - fiber.  Setting a 20g TOTAL carb goal is more restrictive than a 20g NET carb goal.  Hopefully if you're bad at word problems like me, this helps.

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I was wondering if there is a difference between fiber and dietary fiber? Everything I read to subtract says “dietary” but doesn’t say anything regarding the differences.

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Question! I've been on the keto diet for awhile; love it. How does one balance carbs and fat. For instance, if keto is supposed to be low carb and high fat, but one can eat avacado *which is both*, how does one balance that? Or can you just scarf down a whole avacado and count it as good fat? I find no explanations.

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Hi
I have perfect weight according to my height. But the body fat percentage is 30% mostly concentrated in the tummy area. I do cardio for 10-15 min, weights and core exercises. I am also following keto diet since a month and strictly not including any carbs. Do you recommend including little amount of carbs in my pre- workout diet ?
Also will keto diet help in getting rid of my belly fat? And how much time approximately will it take?

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"As a result, fiber does not significantly affect blood sugar and ketosis. In general, you can either aim for 20-25 grams of net carbs or ~ 50 grams of total carbs as recommended by Dr. Steve Phinney and Dr. Jeff Volek."
This is confusing. If for the purposes of ketosis net carbs have the same effect on blood sugar as total carbs, why wouldn't the recommendation be to aim for 50 grams of net carbs (same as total carbs). The Jeff sounds like he is hedging bets. What I get from this is net carbs don't have impact but consume less of them just to be safe? This doesn't clear anything up.

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What happen if i dont reach net carb of 15-20 gram per day? Because there was a day that i dont even reach 5 gram net carb .

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You don't have to reach them - is is a limit, not a target 😊

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What fruits are still acceptable when going keto?

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Most fruits are not but some are included - have a look at this list: Complete Keto Diet Food List: What to Eat and Avoid

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I have a quick question.    If the goal of using keto is to lose weight by using my excess body fat then why is such a high percentage of fat part of the keto diet?    It seems counter-intuitive.

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Hi Dave, although calories do matter, they are not equal (in a high-carb vs high-fat diet). A diet that is high in fat, moderate in protein and low in carbs has natural appetite suppressing effects. Although a ketogenic meal contains more fat, you will feel less hungry and will stay full for longer. To learn more: How To Keto

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I believe the simple answer is that when you eat fat, it doesn't get stored in your body as fat.

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Hello, I have a question.
I understand that total amount of carbs labeled by the companies is being calculated by subtracting fat, protein and in some cases fiber. And net carbs should be calculated by subtracting fiber from total carbohydrates. Now there's a question.
Lets take almonds for example. They have:
Carbohydrate 22 g  
Dietary fiber 12 g  
Sugar 3.9 g
So net carbs for 100 grams of almonds we have 10 grams of carbs.
Usually net carbs include sugars and starch. In the case of nuts there's no starch involved. So what's the rest of 6.1 grams of carbs that we have?
There are many foods that have similar count and i just simply can not find any answer on my question.
Thank you.

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Hello Kateryna, net carbs in this case are 10 (it's total carbs minus fibre), where sugar is included in the net carbs. Net carbs refer to carbohydrates that affect blood sugar. There are many types of carbohydrates - this Wikipedia article explains more: https://en.wikipedia.org/wiki/Carbohydrate

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I am in my 2nd week and no longer losing much weight, so I decided to test my ketones levels via a urine strip. The color came back as large amounts of ketones. Am I sabatoging my weight loss by eating to little carbs? I am keeping it between 20-27 grams of net carbs per day.
TIA for any advice!

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Hello, I am a bit confused on net carbs when the fibre is more than the carbs.
For example: -
http://atlantickitchen.co.uk/products/wakame-seaweed/
The carbs are 7.3g
The fibre is 38.1g
So the net carb is a negative amount?
Can you help to explain.  Thanks 😊

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This is the case of UK labelling - have a look at the "Total carbs vs Net carbs" part of this post 😊

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Hi there,
Just wondering, when using MFP to track macros on a keto diet - do you count green veggies towards the total carb count or can you eat as much green as you like?

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Hi Jo, you need to track all carbs (net carbs) - our KetoDiet app tracks both total and net carbs using an accurate database. As far as I know, MFP and other similar apps use a "shared database" which is created by their users and it's not verified. This means that in such apps, you will likely find duplicates and inaccurate entries. Here's our food list to help you make the right choices (includes carb count in common foods): Complete Keto Diet Food List: What to Eat and Avoid

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I'm not trying to lose weight, i'm at a decent weight but I want to use a potentially healthier fuel for my body than glucose. I'm not a small guy in terms of height and frame, i'm also young and physically active. Now with all this count the carbs in your food advice, or count the net carbs in all foods, or Mark's Daily apple advice to consider all non starchy veggies as free of carbs I find it's impossible to hit enough calories without giving up veggies or getting my veggies and calories but too much carbs balance, is there lee way if you're bigger framewise and have a faster metabolism? If so Mark's approach seems better for me, I lose weight if i'm not getting 2400 cal minimum a day not including exercise days. It seems most keto guidelines are for women and small men.

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Hi Dave, you can maintain or even gain weight on a keto diet by adjusting your fat intake. I'm  not sure I understand - do you find it difficult to get enough calories with or without veggies? There are some high fat foods that will help you get enough calories (avocado, coconut butter, any nut or seed butter and whole nuts, fatty meat cuts, full-fat dairy, etc). Here's more about total vs net carbs: Total Carbs or Net Carbs: What Really Counts?

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I have been cutting out carbs for the last 7 weeks. Have gone from 16'7 down to 14'11. problem I have is for the last week I have stopped losing weight.
I have 2 x Bacon, 2 sausages and 2 fried eggs every morning, Lunch I have 3 boiled eggs and dinner is a mixed grill meat only.
What am i doing wrong, carried out a Keytone test and the colour never changed.
Mark

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Hi Mark, have a look at this post: How To Low Carb: 15+ Common Weight Loss Mistakes

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Hi there
I have just purchased your full app as saw the good comments below but also just noticed that they are from some time ago? Just checking if you keep your apps up  to date with new recipes etc to keep low carb meals interesting and ever changing? I have just started the keto diet and have lost 3 kg but would like to lose another 6-9kg more...
Please can you advise what I could eat during "treat" days as how often one could have a treat day?
Also does this put one out of ketosis and will I feel that "cold turkey" again? If so, will the process of getting back into ketosis be quicker than the beginning?
I am currently trying to eat a total of 25g net carbs per day which seems to work for me, but when I reach my goal weight, how many grams of net carbs do you recommend to maintain that weight if I am now losing weight at 25g net carbs?
Really appreciate your response on this!!
Thank you 😊

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Hi Dee, yes, we still keep working on the App and add new content 😊
We're currently working on the universal KetoDiet App and I frequently add new recipes in the Meals tab + share 2-4 recipes a week on my blog that can be also added to the Planner from the Integrated blog.
When it comes to treats, here's what I'd do... I'd avoid regular sugary treats altogether and only occasionally have low-carb treats (there are so many healthy options to choose from). It's better if you avoid any treats (even low-carb) during the first 3-4 weeks until you get used to the diet. Treats may still cause cravings and you may end up eating more than you would without treats.
After 3-4 weeks, you can can add mini treats like a fat bomb a day: ketodietapp.com/Blog/Filter or other treats 1-3 times a week: ketodietapp.com/Blog/Filter
When it comes to carbs, this level is different for everyone. I eat 30-50 grams net carbs (weight maintenance). You need to try and see how carbs affect your appetite. I hope this helps!

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I'm so thankful for your website! I'm totally new to this keto diet (been reading about it for a week now). I've been Paleo for years, but not as low carb as with this diet.
I'm a bit overwhelmed. I'm not sure it's possible to eat below 50 net carbs a day, with all the hidden carbs in almost everything. I need to lose weight (who doesn't), so I would like to not have more then 30 net carbs, but what is left to eat? Especially if you want to eat 2-3 times a day, not even snacking. I have the fridge full of food, and don't even want to cook it now, less eat it.
I drink 1.7l decaf coffee each day, and the 10% half & half alone has 1 carb/tbsp, and I'm using 2 for each mug, which at the end of the day is 10-12 net carbs. Oy!
Now instead of counting calories I'm trying to figure out net carbs, AND try not to eat too many total calories. Boy is that ever complicated.

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Thank you Monika! It is definitely possible - once you get used to the diet. I find it hard to go over 30 g net / 50 g total carbs simply because of the foods I'm eating on most days. The vast majority of my recipes don't go over 8 grams of net carbs so you have a lot to chose from 😊 I'm not sure why the cream you are using is so high in carbs because it should be almost zero carb (per tablespoon). You may want to check out other brands or use heavy whipping cream instead.
Check out this food list: Complete Keto Diet Food List: What to Eat and Avoid
and these diet plans: ketodietebooks.com/

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Omg- I'm totally in the same boat >😞 This seems so complicated sometimes.. I've been low carb, no sugar for several weeks now and I haven't lost a thing. Super frustrated with myself.

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Do you have a 2 week vegan meal plan for keto? Thank you for the awesome recipes on your blog...

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Thank you Anu! No, I'm afraid I don't. You can use the filtering option in Recipes to see all vegan recipes but no diet plan... To be honest, I don't think it's a good idea to follow a vegan & keto diet because it eliminates most foods and it's very difficult to do it.

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Hi, So I just wanted to clarify a few things.
Should I still aim for between 25-50g carbs even if I were having say 30g fibre but then still having say 50g of actual carbs is that okay or too much?
As for carbs pre and post workout what is a recommended amount to keep in ketosis. My ultimate goal is fat burning whilst maintaining as much muscle as possible, would carbs pre or post workout be more effective for me to achieve my goal?

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Hi Craig, carb intake is different for individuals and I think that it's ok to have up to 50 grams of total carbs - I actually sometimes eat slightly more than that and I'm still mildly ketogenic. 25-30 g net carbs + fiber is fine for most people - It's a myth that everyone is better off on a zero-carb diet and/ or show high ketone readings. Here is more: Do Ketones Matter?
Here is more about post/ pre workout carbs: Ketogenic Nutrition and Exercise: Carbs I'd avoid pre-workout carbs. Whether or you need post-workout carbs depends on the exercise and your goal. I do sometimes have post-workout carbs (usually a sweet potato or root vegetables) after an intense workout to help muscle recovery but not always. These carb-ups may put you temporarily out of ketosis and also ketone levels naturally fluctuate during the day - that's fine.

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I have been living keto for the past month or so, and have come to love my quest bars as the occasional treat. When calculating your nets carbs, do you also subtract sugar alcohols in that case? Or is it simply the carbs - fiber? I have heard conflicting thoughts. Thanks!!

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Hi Amelia, it depends on the sugar alcohols. I don't count some - erythritol has no effect on blood sugar and is very low in calories but other sugar alcohols may affect blood sugar and contain more calories. Here is how I calculate carbs from sugar alcohols: Complete Guide To Sweeteners on a Low-carb Ketogenic Diet

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