After a mad couple of days which ive not been able to eat more than an evening meal and absolutely nothing else i went for a ride today. Usually ride on my own between 40-50 miles, and ive got to say that after 8 miles of the 35 i managed, i felt the weakest ive ever been. Things were fine on the flat until i decided to push which i couldnt sustain for long at all, but the hills were laughable. I had a terrible hankering for 1st gear a couple of times. (im sure i heard a couple of rabbits snigering at the side of the road)

I can only assume that i had very few calories available for what i was asking of my body. I began to wonder if you, Atkins diet riders, have gone through some form of adaption for your bodies to work on what it is used to being fed?
Anyway heres a big thumbs up to you guys who ride on The Atkins diet, you deserve a medal if my you feel the way i do right now.

Im off now to go and have a word with those bunnies.

The biggest challenge when switching to a low carb lifestyle is the 1st few days - up to 2 weeks. It takes time for your body to switch from burning sugar that you eat for energy to burning the stored fat for energy. Once I get past that, I have very sustained energy levels. If I'm riding much longer than 1-1.5 hours though, I have to eat something with complex carbs in it to sustain me during the ride.

To start with, Atkins is not a fast. Atkins is low-carbohydrate, but adequate calories.

Yes it does take a while for the body chemistry to change to support exercise after starting. The first two weeks or so are not a good time to exercise. Your body has not yet built up the hormones needed to burn more fat while exercising. After my body adjusted, I was able to bike at higher levels for longer periods of time. Burning fat instead of carbs is great for endurance.

In conclusion, high-fat dietary conditioning increased fat oxidation, and although the main effects were not statistically significant, there was some evidence for enhanced ultra-endurance cycling performance relative to high-carbohydrate. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12037719&dopt=Abstract

Conclusions
Both observational and prospectively designed studies support the conclusion that submaximal endurance performance can be sustained despite the virtual exclusion of carbohydrate from the human diet. Clearly this result does not automatically follow the casual implementation of dietary carbohydrate restriction, however, as careful attention to time for keto-adaptation, mineral nutriture, and constraint of the daily protein dose is required. http://www.nutritionandmetabolism.com/content/1/1/2

Burning fat instead of carbs is great for endurance.


I disagree. Ever bonk? That's your body without any carbs to burn. You'll be limited to just riding slow if fat (or catabolized muscle) is your only fuel and you will feel like crap. Atkins and endurance sports are just not a good mix.

I disagree. Ever bonk? That's your body without any carbs to burn. You'll be limited to just riding slow if fat (or catabolized muscle) is your only fuel and you will feel like crap. Atkins and endurance sports are just not a good mix.

The adaptation Atkins riders experience is riding slower.

I disagree. Ever bonk? That's your body without any carbs to burn. You'll be limited to just riding slow if fat (or catabolized muscle) is your only fuel and you will feel like crap. Atkins and endurance sports are just not a good mix.

A trained athlete can obtain about 200 calories per hour from fat metabolism. That's about 12 mph.

I did the Southbeach diet a year and a half ago. There are 3 stages. The first stage lasts two weeks and I experienced what you did during that stage. I gave up on riding for those 2 weeks. Without carbs, your body loses it's stores of glycogens and there is noting to fuel your body on eforts over 10-14 mph because the fat metobolism process is too slow to keep up on harder efforts.

In the second stage, you add some carbs back in. Fruits, vegetables and other low gylcemic index carbs. Once I got some carbs into my system I was able to ride again after a couple of days. At first I would bonk in less than an hour and I was able to get up to 1.5 to 2 hours without bonking.

Once you get to the weight off you go to the third stage which is js just maintenance. Just avoid high gylcemic carbs (except when doing long rides) and bad fats.

It's best to do phase 1 and phase 2 in the off season when you are not training or riding hard.

I got down from 185 to 160 pounds doing this. (@ 6'0")

A trained athlete can obtain about 200 calories per hour from fat metabolism. That's about 12 mph.
I must not be a trained athlete as I have ridden almost 5 hours at speeds much higher than 12 mph. My average speed has actually increased since I adapted to low-carb. I can now do climbs with my double that I used to have to use a triple for (of course a portion of that is due to the weight loss). As I don't race, I do not know how the diet change would have affected me in that environment.

I had two serious bonks when I used to stuff myself with carbs. Since I reduced my carbs level to Atkins levels, I have not bonked (three years). Without the excess glucose to rely on, the body burns a higher level of fatty acids for its energy needs. This reduces the muscles' needs for the glucose that they used to rely on. To fuel me on longer rides I take along some nuts. They provide enough carbs to replace the glucose that I am using, provide protein for muscle repair and fat for taste and satiation. I do make sure that I have lots of electrolytes in the fluids that I take along.

There have been many other positive changes due to reducing carbs. I went from three drugs to control cholesterol to none. My blood sugar went from near diabetic to normal. My liver enzymes are all normal for the first time ever. I no longer get sleepy after lunch. I wake up feeling refreshed and not groggy. My hair is not as thin as it was, but my hairline is still receded. Oh, and I no longer go around being hungry.

I must not be a trained athlete as I have ridden almost 5 hours at speeds much higher than 12 mph. My average speed has actually increased since I adapted to low-carb. I can now do climbs with my double that I used to have to use a triple for (of course a portion of that is due to the weight loss).

Since I reduced my carbs level to Atkins levels, I have not bonked (three years).

There have been many other positive changes due to reducing carbs. I went from three drugs to control cholesterol to none. My blood sugar went from near diabetic to normal. My liver enzymes are all normal for the first time ever. I no longer get sleepy after lunch. I wake up feeling refreshed and not groggy. My hair is not as thin as it was, but my hairline is still receded. Oh, and I no longer go around being hungry.

I have to ask- how much of these changes can be attributed to your new low-carb diet, and how much to your training? I'm not knocking low-carb diets, they have been proven effective for lowering cholesterol, helping with diabetes, etc. But so have increased exercise & weight loss. It seems to me alot of what you mention could also be the result of training. At least 50%, possibly more.

I have to ask- how much of these changes can be attributed to your new low-carb diet, and how much to your training? I'm not knocking low-carb diets, they have been proven effective for lowering cholesterol, helping with diabetes, etc. But so have increased exercise & weight loss. It seems to me alot of what you mention could also be the result of training. At least 50%, possibly more.
My training is essentially the same. If anything my mileage is down somewhat.

I know people who have had to go to the hospital while on Atkins just because they didn't have the energy to carry on daily life. They just got very ill from the lack of carbs and thus energy.
This is an otherwise healthy person who exercises some, but not like riding 50 miles/day.

This is why I believe in the everything in moderation deal. Now what I believe and what I actually do are two different things...

I thought the point of the high-protein/low-carb diet was partly that it kept you from going back to the feed trough between meals...during the summer, if I'm exercising a lot and eating frequently anyway, it doesn't make as much sense.

During the winter, I do find that cutting down on sugar and carbs and getting plenty of protein keeps me from getting tired and grumpy (hypoglycemic), but then, I'm not burning as much energy either.

Off to make pasta - yum!

I must not be a trained athlete as I have ridden almost 5 hours at speeds much higher than 12 mph.

The bonk is what happens AFTER you've run out of carbs. You have stored glycogen in your muscles and liver, and you have food in your digestive tract when you start a ride. AFTER you exhaust those, along with burning the 200 calories per hour of fat, THEN you bonk. It is quite conceivable that you could start a ride with 2500 or more calories in stored glycogen and food in your gut, allowing you to burn 700 calories per hour for 5 hours and just run out of fuel. Don't confuse yourself into believing that your diet is the key to success rather than your training.

The bonk is what happens AFTER you've run out of carbs. You have stored glycogen in your muscles and liver, and you have food in your digestive tract when you start a ride. AFTER you exhaust those, along with burning the 200 calories per hour of fat, THEN you bonk. It is quite conceivable that you could start a ride with 2500 or more calories in stored glycogen and food in your gut, allowing you to burn 700 calories per hour for 5 hours and just run out of fuel. Don't confuse yourself into believing that your diet is the key to success rather than your training.
As I consume approximately 50 grams of carbs a day and exercise in some form or another at least every other day, I doubt that if I was still burning lots of glycogen while exercising that I would not bonk rather quickly. Yesterday I did a 12 mile walk after lunch and realized at 11:30PM that I had not eaten super. I ate a handful of nuts and went to bed. Only a few carbs to replace any lost glycogen. Breakfast was sausage and eggs. Lunch was a burger patty with cheese and some veggies. Again few carbs. I did a 25 mile ride and had no problems. I am going to have some chicken thighs and veggies for supper with some berries for dessert. Not a whole lot of carbs. If carbs are the key to exercise then I should have been in a continuous bonk from three years ago.

My training has not changed. I average about 3500 miles a year on the bike and quite a few miles of walking/hiking.

I am sure that I could a long/hard ride and get to the bonk stage, but I see no purpose in finding out what that would be.

I have bonke in the past when I was a carb fanatic and definitely agree that 12 mph is a typical bonked maximum pace. It just hasn't been a problem since I adjusted to low-carbs.

As I consume approximately 50 grams of carbs a day and exercise in some form or another at least every other day, I doubt that if I was still burning lots of glycogen while exercising that I would not bonk rather quickly. Yesterday I did a 12 mile walk after lunch and realized at 11:30PM that I had not eaten super. I ate a handful of nuts and went to bed. Only a few carbs to replace any lost glycogen. Breakfast was sausage and eggs. Lunch was a burger patty with cheese and some veggies. Again few carbs. I did a 25 mile ride and had no problems. I am going to have some chicken thighs and veggies for supper with some berries for dessert. Not a whole lot of carbs. If carbs are the key to exercise then I should have been in a continuous bonk from three years ago.

My training has not changed. I average about 3500 miles a year on the bike and quite a few miles of walking/hiking.

I am sure that I could a long/hard ride and get to the bonk stage, but I see no purpose in finding out what that would be.

I have bonke in the past when I was a carb fanatic and definitely agree that 12 mph is a typical bonked maximum pace. It just hasn't been a problem since I adjusted to low-carbs.
I gotta say, Mikebiker is right on the money regarding Atkins approach and cycling. I did Atkins a year ago and shed 34lbs. over several months. Although the two week induction phase can be brutal as your body converts to ketosis, it gets much easier afterwards. While I did Atkins I averaged 10-12hrs. a week of cycling and swimming and found that my glycogen blood levels did not vary as much with low glycemic index foods than with carb-laden power bars etc. that I was eating. I have , in effect been able to sustain higher levels of intensity for longer periods of time than before without bonking.
I also don't get the sugar craving that I used to after a tough ride. The trick is to find the amount of carb intake that is "best" for you. Mikebiker's is 50 grams, I found mine is about 90 grams per day.
I think what a lot of people don't understand about Atkins is that a big portion of it is just NOT eating "junk" carbs; candy, cheese-doodles, potato chips etc. I have replaced "junk" carbs with broccoli, lean meat, and other nutrient-rich, slow digesting, low glycemic index foods.
Perhaps the only downside to this way of eating that I have found is that your legs take an extra day to recover after riding all week.

The bonk is what happens AFTER you've run out of carbs. You have stored glycogen in your muscles and liver, and you have food in your digestive tract when you start a ride. AFTER you exhaust those, along with burning the 200 calories per hour of fat, THEN you bonk. It is quite conceivable that you could start a ride with 2500 or more calories in stored glycogen and food in your gut, allowing you to burn 700 calories per hour for 5 hours and just run out of fuel. Don't confuse yourself into believing that your diet is the key to success rather than your training.
I have been riding steady now for about three years and logged just over 4000 miles last year. Succes whether it be speed, mileage , hill climbing, or sprints, takes both the right diet and training. You can speculate on percentages if you like but the bottom line is that it takes both and everyone's metababolism is differant.
As far as the low carb thing goes I have done it, been succesful at it, and still cut back every so often to drop some weight when needed.
My experiance is that it is very tough during the first few weeks as mentioned in another response. Personally it is also more difficult for ME to maintain high end training while on a Low Carb diet. That being said you typically burn more fat at a lower pace anyway. 12-15 mph for me per V02 test. If it works for you Go FOR IT!

Atkins, low carb diet is a stupid idea.

Ketosis is an unnatural state of metabolism.

You wanna diet? Eat whole foods, unprocessed. Exercise.

Atkins and endurance sports are just not a good mix.

Couldn't have said it better. ;)

Atkins, low carb diet is a stupid idea.

Ketosis is an unnatural state of metabolism.

You wanna diet? Eat whole foods, unprocessed. Exercise.
You are certainaly entitled to your opinion and I agree that whole unprocessed foods are fantastic however there are thousands and thousands of people out there including myself that low carb dieting has helped. In addition I have frineds that live an hour away from any store an it's not a health food store. In general whole unprocessed foods are hard for them to come by.
Ketosis is unnatural and is not a recommended state to remain in. Just a way to wean oneself from a high carb diet. I think the comment of "stupid" is a little harsh.
Stupid is as stupid does.

Atkins while OK for more sedentary folks who don't want to exercise, yet still lose weight has no place if you are trying to ride/run or whatever at any reasonable speed for any length of time.

As another poster said, Adkins and endurance sports don't mix well..

In reality the mix is more like mixing water and oil.