Low carb and cycling...
 

Hey guys, I am 225 now but have been 240 in the past. Low carb has worked very well for me in the past, and I now want to get the weight off asap. Is there any problem with very low carbs and cycling 15-20 miles per ride 5 days a week? I know that low carb makes sense, but can it be a problem with this much exercise?

IIRC, there's some kind of exercise provision in the lo-carb bible? I've got a few family members on various forms of it and I'd swear I heard them mention getting to trade a half hour of exercise here for a grain of rice there.

what would the problem be?

you may eventually reach a level where adding back more carbs will provide additional energy to make the ride go quicker but if the goal is simply increased cardio along with fat burning. go for it

It's possible to experience low blood sugar events while doing Low carb and exercising. The bonk beast can hit early....been there. ;)

You really shouldn't try to lose weight with a "low" or "high" anything diet. The key is reduced total quantities, but in balance. When you use an unbalanced diet to try to lose weight rapidly, you're risking your health as well as setting yourself up to gain it all back again once you stop the diet.

I thought carbs were important for physical activity and the reason for pushing lower carbs is because the most exercise the average person gets is walking to their car. No exercise, no need for all those carbs that don't get burned.

Doesn't low carb + high exercise=bonk (and not the good kind of bonking)?

Eat less calories than you burn, fat along with some muscle will get burned. Important to keep to satiated or just under, overeating any single meal will cause a sort of storage syndrome where the body thinks you are stocking up for a reason.

It's possible to experience low blood sugar events while doing Low carb and exercising. The bonk beast can hit early....

This is what I'm afraid of I guess. Before cycling I could lose 3 pounds a wk. and never felt better physically. I'm just wondering if this could be dangerous with cycling. If you are burning fat only for fuel (ketosis), can you still continue cycling? I know from my own experience that a low fat, high carb. diet does not work at all. But I am not sure about the low carb plus high execise option...

i wouldnt deny your body of what it wants. i.e. what most are preaching...... balanced everything. IMO only you know what your body requires. instead of eating less, eat better and work harder. the body likes you better.

if your diet doesnt slow you down and hasnt left you with no gas in the tank for the start of the next week go for it.

after 10 weeks or so of 5 days a week riding hard i found i needed to up my intake alot. im losing weight, but if im drained due to diet i cant lose weight if im off the bike more than on.

+1 for truth. I have tried the low carb, low fat, low etc, diets, and they all work for a time. I always found that the problem was getting off of them. By reducing the amount of food in a balanced amount, and eating better, I think that you set yourself up for a more sustainable future.

For the past month, for example, I am running a calorie ratio of 48% carb, 21% protein, 26% fat (less than 10% saturated, mostly mono unsat and poly unsat), and <5% misc like alcohol and stuff. I would like to increase the protein a bit by trading off some fat, but so far it is working.

However, I am averaging only 1900+ calories a day, and am not eating chips, and no soda, or any HFCS (high fructose corn syrup). I am trying to eat as much whole/unprocessed as possible.

This more balanced approach, with exercise, is working MUCH better than anything else. Is the weight flying off? 18lbs so far. Not as fast as other methods, but my diet structure is sustainable-I won't need to change anything or worry about what is on the list or not. Exercise?CHECK!! I love biking now-I commute every, or nearly every, day, and incorporate the riding into othe activities like coffee, short errands, etc. I am saving a bunch of money too, though bike repairs just ate into that a bit.

Just my .02.......

I think I read one time in SciAm or somewhere that biochemists are pretty close to saying that as long as you get the minimum necessary amounts of certain things (ie minerals, aminos, vitamins) your body will cross-convert fats, sugars and proteins as needed. The trouble with that being the time and energy demand involved. Obviously you can't eat pure protein and expect to have the available bloodsugar for an all-day tour. the protein might all be converted as needed in a 2 day span instead of the 1 day you needed it.

So with that i mind, until I start bonking or experiencing symptoms of other specific deficiencies, I'm worrying more about ramping UP my activity and eating generally good food in moderation with little concern over the fat/carb/protein balances.

A thing to probably worry about most on the low-carb thing is that you should be twice as worried about refueling on the ride as others.

Best I can tell you, keep your hydration up....doing low carb/High Protein with insufficient hydration can damage your kidneys, because once you run out of easily available glucose, you switch to the Fat/Protein metabolism and among other things run a lot of fractional proteins and uric acid through our kidneys. I would strongly suggest you carry sublingual glucose tabs like a diabetic would with you, because when the bonk hits bad, you'll have trouble thinking, and even opening up a packet of food. Your brain can ONLY metabolize glucose, and nothing else.

Early symptoms of Hypoglycemia include sudden mood shifts, headache, immediate energy drop, and can extend to severe cognitive difficulty, even, later. If you are riding and experience the headache and energy drop, and begin to have issues, you can always pop a glucose tab if necessary. Bonking is really nothing more or less than exercise induced Hypoglycemia in a fairly extreme expression.

Why not try a balanced diet and not a high carb or low carb diet? Look at doing a diet that consists of everything!!!! Fruits and vegetables are great, have a little meat here and there, keep your fibre up with the fruits and vegetables and eat some carbs also. Watch your calorie intake, instead of your carb intake. What are the fats your are eating?

Ok guys, time for a little low-carb myth-busting.

1) The brain can run on Glucose or on Ketones which are produced by burning fat. The brain actually runs more efficiently with ketones but the 'modern' or agriculturally-based diet provides access to carbohydrate in sufficiant quantity that glucose is used first.

2) The kidney damage issue has been disproven for several years now but increased fluid intake is natural due to the diuretic nature of the diet. The diuretic effect is equivalent to that of 'water pills' as used for hypertension. (which means that those under drug treatment for hypertension need to communicate with their doctor when low-carbing as they may quickly end up over medicated)

3) The hypoglycemia symptoms result from an imbalance between blood glucose levels and insulin levels. In a healthy person, glucose does not drop to dangerous levels due to the liver's ability to generate glucose from non-carbohydrate sources. This is not an attempt to say that 'bonking' doesn't happen on low carb but that 'bonking' occurs when the body has not sufficiently acclimatized to a primarily fat-burning metabolism vs primarily carbohydrate-burning metabolism. There have been at least a couple good studies done comparing high-carbohydrate fueling for athletic performance vs low-carbohydrate fueling for athletic performance. In the early stages the result has been exactly as you all report. However, over time, the low-carb performance level improves to at least equal to the high-carb fueling

This leaves a person involved in high output athletic activities with 2 choices: A) increase carb intake in the diet to adjust for the increased activity B) Reduce athletic activity to comfortable level and permit the body time to adjust to the metabolic change of processing. Most people chose (A) however the second option is still available and effective.


I was reminded of this listening to an author on the radio recently. Anyone who's interested in the history of dietary dogma from a reasearch point of view might be interested in this book. "Good Calories, Bad Calories" by Gary Taubes. He's not a 'diet book' guy so it should be interesting reading.

(reference previous post) Actually you CAN EAT pure protien and expect have this provide available blood sugar. Excess protein is converted to glucose through the liver. This is part of the reason that many people have a tough time with low-carb, because they are eating too MUCH protein and end up having higher glucose levels than they realize.

I do know this sounds bizzare

"There have been at least a couple good studies done comparing high-carbohydrate fueling for athletic performance vs low-carbohydrate fueling for athletic performance. In the early stages the result has been exactly as you all report. However, over time, the low-carb performance level improves to at least equal to the high-carb fueling."

Can you cite these studies? I would very much like to see the biochemistry. - TF

(my mistake, there is only one direct reference)

The one referenced by Atkins is found here I believe: European Journal of Applied Physiology and Occupational Physiology 1994: 69(4): 287-93 I would suspect there are more even if engaged to rebut the data discussed.

I don't have access to that particular Journal from my university Journal access that I have found, yet. I'll keep checking

TaDAH!!!

Reference found, Abstract follows

Estelle V. Lambert1 http://www.springerlink.com/images/contact.gif, David P. Speechly1, Steven C. Dennis1 and Timothy D. Noakes1
(1) Liberty Life Chair of Exercise and Sports Science, MRC/UCT Bioenergetics of Exercise Research Unit, Department of Physiology, University of Cape Town Medical School, Observatory 7925, Cape Town, South Africa
Accepted: 25 April 1994
Abstract These studies investigated the effects of 2 weeks of either a high-fat (HIGH-FAT: 70% fat, 7% CHO) or a high-carbohydrate (HIGH-CHO: 74% CHO, 12% fat) diet on exercise performance in trained cyclists (n = 5) during consecutive periods of cycle exercise including a Wingate test of muscle power, cycle exercise to exhaustion at 85% of peak power output [90% maximal oxygen uptake ( http://www.springerlink.com/content/...TeX2GIFIE1.gif O2max), high-intensity exercise (HIE)] and 50% of peak power output [60% http://www.springerlink.com/content/...TeX2GIFIE2.gif O2max, moderate intensity exercise (MIE)]. Exercise time to exhaustion during HIE was not significantly different between trials: nor were the rates of muscle glycogen utilization during HIE different between trials, although starting muscle glycogen content was lower [68.1 (SEM 3.9) vs 120.6 (SEM 3.8) mmol · kg –1 wet mass, P < 0.01] after the HIGH-FAT diet. Despite a lower muscle glycogen content at the onset of MIE [32 (SEM 7) vs 73 (SEM 6) mmol · kg –1 wet mass, HIGH-FAT vs HIGH-CHO, P < 0.01], exercise time to exhaustion during subsequent MIE was significantly longer after the HIGH-FAT diet [79.7 (SEM 7.6) vs 42.5 (SEM 6.8) min, HIGH-FAT vs HIGH-CHO, P<0.01]. Enhanced endurance during MIE after the HIGH-FAT diet was associated with a lower respiratory exchange ratio [0.87 (SEM 0.03) vs 0.92 (SEM 0.02), P<0.05], and a decreased rate of carbohydrate oxidation [1.41 (SEM 0.70) vs 2.23 (SEM 0.40) g CHO · min–1, P<0.05]. These results would suggest that 2 weeks of adaptation to a high-fat diet would result in an enhanced resistance to fatigue and a significant sparing of endogenous carbohydrate during low to moderate intensity exercise in a relatively glycogen-depleted state and unimpaired performance during high intensity exercise.
Key words High-fat diet - Carbohydrate - Fat metabolism - Exercise performance - Fatigue

Link http://www.springerlink.com/content/...fa3463a85&pi=2

Found another one with acutal performance data

The Effect of Nutritional Manipulation on Ultra-Endurance Performance: A Case Study

Authors: Anna L. Robins a; Don M. Davies a; Gareth E. Jones b
Affiliations: a School of Community, Health Sciences and Social Care, University of Salford, Greater Manchester, UKb Department of Biological Sciences, University College Chester, Chester, UK
DOI: 10.1080/15438620500222505
Publication Frequency: 4 issues per year
Published in: http://www.informaworld.com/mpp/cach...rnal_small.png Research in Sports Medicine, Volume 13, Issue 3 July 2005 , pages 199 - 215
Subject: Medicine;
Formats available: HTML (English) : PDF (English)

Previously published as: Sports Medicine, Training and Rehabilitation (1057-8315) until 2003
Article Requests: Order Reprints : Request Permissions

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Abstract

The Atlantic Rowing Race requires teams of two to cover 3,000 nautical miles over 40-90 days. During this ultra-endurance event, competitors require substantial energy intake to meet metabolic requirements; therefore, sufficient physiological and nutritional support is paramount. Two highly trained males (aged 46) engaged in two 14d dietary interventions, with a 14d recovery period in between, to investigate the effect of such interventions on physiological (cardiovascular, cardiorespiratory, and blood-based measures) and performance-based (distance and split time) parameters during an ultra-endurance (2h on 2h off, for 24h) laboratory-based rowing protocol at 60% VO2max. Diet 1: high fat (HF) [60% fat, 30% carbohydrate and 10% protein] and Diet 2: high carbohydrate (HC) [20%, 70% and 10% respectively]. A greater distance was rowed by both subjects (155, 329m and 134, 797m vs 130, 089m and 122, 112m) with a concomitant reduced heart rate, volume of oxygen uptake, and respiratory exchange ratio, following the HF as opposed to HC dietary intervention. In summary, ultra-endurance performance was enhanced following a 14d HF diet, without apparent implications on liver function and overall lipid profile.

Keywords: ultra-endurance rowing; high fat; high carbohydrate

http://www.informaworld.com/smpp/con...38620500222505

Just about everything I've read on this I have to agree with,esaunders. Hammer nutrition keeps sending me a lot of reading material on this subject, and they say just about the same thing. I want to lose more weight too, but I'll try and take it off with exercise. If you don't have enough carbs and protein your muscles will start losing strength as well.

Atkins didn't rode bikes... just saying.

No he didn't Reuben, but the study he referenced was using cyclists.

The first paper used cyclists, the second used rowers. Both are highly aerobic activities and both studies were very performance based. Both found that after 2 weeks of the low carb diet high-intensity performance was unimpaired or enhanced.

As in anything, your milage may vary, but I find these scientific papers that specifically put forth performance data to back up their conclusions interesting and worth consideration. I also find it interesting that the rebuttal papers do not include such hard data in their abstracts.

Why does it matter that Atkins was the one that brought the study to my attention? The man was a freakin' cardiologist, he knew how to read scientific papers.

+1

Low-carb diets are the devil. That **** is NOT good for your body in the long-term, not good at all.

Hmm, what do you base your opinion on? I know of many people who have been using extremely low carb diets, on the order of less than 60 grams a day, for many years.

to be fair, ultra endurance sports rely on fat no matter what your diet is. there is a reason why they load the cyclist up with fatty fish and good oils in the TDF. from what i've heard after ~40 min you start using a lot of fat. cycling and rowing are clearly a long sustained efforts so fat is probably the way to go. also the energy density is the only way those two guys could live off of a boat for 40+ days with out any support. there is no way they could load 2.5x the food to live off of carbs.

Our bodies are pretty amazing power plants. They run on just about anything we put in them. They store energy (fat) on just about anything. They mainly store what we don't burn off. So, if you like your protien, carbs, fat or what ever eat it. Just don't eat more than what your body needs for the day.

Our bodies adapt to all different eating plans, or diets. Its really amazing when you think about it. Sue can eat nothing but fruit, Bill lives off a half a cow a day, and Dave and Fran only eat raw veggies. Yet all can bike a century.

Not a true scientific study, but I watched Discovery Health channel where they took six vegans and converted them to a high protien diet to see if they improved there strength. Three ate vegan protien sources and three ate flesh protien. After three onths, no significant signs of improved strength in the six subjects.

Dr Ellington Darden, of High Intensity Training fame, sports a plan (for body builders even) for a high carb diet instead of an ultra low carb/high protien diet. And he has ALOT of subjects, from all body shapes and types, that has went through his program.

Personally, I have never once craved a steak or egg while maintaning a balanced diet. But I would have sold my first born for a piece of bread while doing Atkins!

Someone really smart one said that losing weight is 90% diet and 10% exercise. I believe that. If you ride for 250 calories, then eat 300 alories of "diet ice cream", then you are going to be fat. You are intaking more than you burning and your body will store it. Besides, when I'm exercising, I don't want to eat too much. I don't want to undo that great ride or workout. I want to be able to buy a new smaller pair of shorts or shirt later instead of eating a no al fudge bar now.

If you like the high pro diets, do it. Your body might even excel on that type of diet plan. Same with a high carb or high fat diet. But, that doesn't mean EVERYONE's body will. I think it has to do with metal outlook also. And, its harder to stay on an exclusion diet than a balanced one.

BTW, extra piece of info for everyone.....Have you ever wonder why you lose weight on a "new" diet than on one you have already tried? Its because you know how to cheat on the older diet, and not the newer one (yet)! Read that in the Drs office this week.

Jerry