Dietitian's corner

[Sports Certified Dietitian]

Hi everybody,

 

I'd like to introduce myself and offer my services to you.

 

I'm a Sports Certified Dietitian in private practice who has a passion for mountain biking. I see clients/patients on a daily basis who need and want to improve their eating for all sorts of reasons - health and sports being two of those.

 

Because nutrition plays a major role in promoting sports performance, recovery, injury prevention and general health and well-being, what you eat and drink before, during and after exercising/racing is vital if you want to get the most out of your hard training/competing.

 

What I'm happy to do is answer some questions on a weekly topic that you may have concerning optimum eating and nutrition. As my time is obviously limited, there is a limit to my input, but I shall try my best to answer questions that you may have. Please base your questions on the weekly topic ONLY so that we can manage the whole thing effectively.

 

I do not profess to know it all, but what I can offer is an educated opinion based on someone that is in the nutrition field on a daily basis. As I am a registered Dietitian, with a competitive background, I understand the mind set of an athlete and what it takes to train hard and do well in one's sport. I also have access to substantial resources, and can ensure that any input I give is for the most part, evidence-based and as current as possible.

 

What I shall do on a weekly basis is write about and upload graphics on something that is pertinent to mountain biking/cycling in general. There are many topics that can be addressed as you can well imagine, but my first topic that I shall look at is... body weight.

[Sports Certified Dietitian]

Bodyweight

 

If one looks at good cyclists, they don’t resemble sprinters, but are lean and functional for cycling. Carrying excess bodyweight, be it muscle or especially fat, is detrimental to cycling performance.

 

Disregarding bike and equipment weight (see other forum topics), James C. Martin, Ph.D., assistant professor in the department of exercise and sport science at the University of Utah, calculated that for every 5 pounds (2.3 kg) additional weight, a rider would take 30-seconds longer to get up a 5-km, 7% incline hill.

 

A heavier rider will have to produce more watts than a lighter rider to get up the same hill. An 80 kg rider producing 100 watts for an hour will need 432 kcal versus 414 kcal for a 60 kg rider. (see attached graph). Watts means energy needed…

 

A heavier rider will require more energy per hour of cycling than a lighter rider. (see attached graph).

 

A heavier rider will require more energy per kilometre of cycling than a lighter rider. (see attached graph).

 

Even at rest, a heavier person burns up more energy than a lighter person (1728 kcal versus 1296 kcal for an 80 kg and 60kg person).

 

Energy stores, especially muscle glycogen, which is needed for higher intensity exercise like mountain biking, is limited. If you have higher energy needs (due to being heavier as opposed to lighter) which deplete your muscle glycogen stores quicker, your performance will suffer.

 

Ensuring your muscle glycogen is topped up for rides is vital (or you are adequately fat-adapted), but dropping excess weight is also vital if you want to make the most of your training/competing.

 

Excessive weight-loss can be detrimental to health as well as sporting performance, so losing weight and getting into shape needs to be managed carefully to avoid the hazards.

 

What should you weigh ideally?

 

The H-squared method can be used to give you a basic idea. Every person is different, and hence personal circumstances need to be taken into account as well.

 

For female adults (18+) take your height and square it, multiplying by 19 and 24 to get your weight range in kg. For example, a 1.68 m female will have an ideal weight range of 53.6 kg – 67.7 kg with an average of 60.7 kg. [(1.68 x 1.68) x 19 and (1.68 x 1.68) x 24].

 

For male adults (18+) take your height and square it, multiplying by 20 and 25 to get your weight range in kg. For example, a 1.68 male will have an ideal weight range of 56.4 kg – 70.6 kg with an average of 63.5 kg [(1.68 x 1.68) x 20 and (1.68 x 1.68) x 25].

 

Now that you know the effect of being heavier and have a basic reference for what you should weigh, next week I shall cover how your weight should be divided i.e. body composition.

 

References:

http://brisbanebike.blogspot.com/2011/07/watts-and-cycling.html

http://www.smartcycles.com/bike_weight.htm

http://www.livestrong.com/article/475642-how-much-does-body-weight-affect-your-cycling-speed/

[cadenceblur]

Nice initiative!

I am particularly interested in the role of carbohydrate and protein for post ride recovery and particular, what is the best form of carb to take in post exercise.

[Patchelicious]

Nice initiative!

I am particularly interested in the role of carbohydrate and protein for post ride recovery and particular, what is the best form of carb to take in post exercise.

 

Have a read on Peter Attia's blog... he has experimented with all of those metrics.

 

http://eatingacademy.com/

[VicanZA]

welcome, to long to read but in short.

 

Call me if you wanna ride strong or not be a buffalo...

[Wobbles]

Good luck in trying to find this particular blog - I couldnt!

[candz1]

Thank you..interesting read. Now I know what I need to do to to ride faster up a hill..

[HBO]

Hi Craig, thanks for the initiative.

 

I am currently on banting to get to my goal weight which is (according to a doctor who thoroughly tested me) 85 kg. Being 1.87 m it is at the higher end of what you also recommend.

Currently I am at 98 coming down from 110 since the Argus.

 

However I struggle to train at high intensity levels and my HR is 10 - 15 bpm higher than normal. Resting as well as during training.

My common knowledge tells me that the higher my HR the more kilojoules my body will burn, thus using more energy. 

 

Is this because my body is not Fat-Adapted yet, it is about 10 weeks now?

Should I add a little carbs to my diet, even if it is just on training HIIT days? If so wouldn't this delay the fat-adaptation/ ketosis process?

 

Will the HR levels normalise as my body reach Ketosis/ fat- adaptation?

[cadenceblur]

I always knew , but there's only so much weight one can lose.

[cadenceblur]

Hi Craig, thanks for the initiative.

 

I am currently on banting to get into my goal weight which is (according to a doctor who thoroughly) tested me 85 kg. Being 1.87 m it is at the higher end of what you also recommend.

Currently I am at 98 coming down from 110 since the Argus.

 

However I struggle to train at high intensity levels and my HR is 10 - 15 bpm higher than normal. Resting as well as during training.

My common knowledge tells me that the higher my HR the more kilojoules my body will burn, thus using more energy. 

 

Is this because my body is not Fat-Adapted yet, it is about 10 weeks now?

Should I add a little carbs to my diet, even if it is just on training HIIT days? If so wouldn't this delay the fat-adaptation/ ketosis process?

 

Will the HR levels normalise as my body reach Ketosis/ fat- adaptation?

That's some nice weight loss! well done. Interesting number that 85kg though. We're the same height and I weigh 93kg and would not consider myself to be overweight.

What testing protocols have been used to establish this as the goal weight?

[Wobbles]

Hi Craig, thanks for the initiative.

 

I am currently on banting to get to my goal weight which is (according to a doctor who thoroughly tested me) 85 kg. Being 1.87 m it is at the higher end of what you also recommend.

Currently I am at 98 coming down from 110 since the Argus.

 

However I struggle to train at high intensity levels and my HR is 10 - 15 bpm higher than normal. Resting as well as during training.

My common knowledge tells me that the higher my HR the more kilojoules my body will burn, thus using more energy. 

 

Is this because my body is not Fat-Adapted yet, it is about 10 weeks now?

Should I add a little carbs to my diet, even if it is just on training HIIT days? If so wouldn't this delay the fat-adaptation/ ketosis process?

 

Will the HR levels normalise as my body reach Ketosis/ fat- adaptation?

 

 

I speak from personal experience. I was on Banting for 4 months. I lost weight initially but then my body went back to what it liked. I was very strict and had no bread and very very little rice, potatoes, etc. I went back to my dietician...result I was exactly the same weight and body fat as when I started!!

 

My cycling? This went down the tubes very fast and like u, my HR went high and ran out of energy FAST at high intensity. It took me 4 weeks after stopping Banting to regain my strength and start riding well again.

 

Conclusion - I felt fine on Banting for normal activities but it does NOT work for cyclists. One should lose weight by portion control on a normal diet rather than go on the dodgy Banting fad.

[cadenceblur]

It's all about balance in my books, I don't go crazy on the carbs but I do take them particularly post work outs and while racing. Even Noakes recommends higher carb intake for those that engage in high intensity training or racing.

[Patchelicious]

I speak from personal experience. I was on Banting for 4 months. I lost weight initially but then my body went back to what it liked. I was very strict and had no bread and very very little rice, potatoes, etc. I went back to my dietician...result I was exactly the same weight and body fat as when I started!!

 

My cycling? This went down the tubes very fast and like u, my HR went high and ran out of energy FAST at high intensity. It took me 4 weeks after stopping Banting to regain my strength and start riding well again.

 

Conclusion - I felt fine on Banting for normal activities but it does NOT work for cyclists. One should lose weight by portion control on a normal diet rather than go on the dodgy Banting fad.

That is your conclusion based on a test on one person. Stating that is doesnt work for CYCLISTS and that its a FAD are very big statements if generalizing.

 

Have a read on Peter Attia's blog, he says different and has data to back it up.

 

Edit: I am not here to argue for or against LCHF for cyclists. I am simply saying you cannot draw a conclusion based on an individual result.

[Captain Fastbastard Mayhem]

That is your conclusion based on a test on one person. Stating that is doesnt work for CYCLISTS and that its a FAD are very big statements if generalizing.

 

Have a read on Peter Attia's blog, he says different and has data to back it up.

 

Edit: I am not here to argue for against LCHF for cyclists. I am simply saying you cannot draw a conclusion based on an individual result.

IT'd be called an anecdote.

[Wobbles]

That is your conclusion based on a test on one person. Stating that is doesnt work for CYCLISTS and that its a FAD are very big statements if generalizing.

 

Have a read on Peter Attia's blog, he says different and has data to back it up.

 

Edit: I am not here to argue for or against LCHF for cyclists. I am simply saying you cannot draw a conclusion based on an individual result.

I did say it was my personal experience!! However two other members of our group have tried Banting and experienced similar symptoms. Both of them have lost ground to the rest of us and have never regained their pre-Banting form. They also lost an incredibly small amount of weight.

 

I am not sure how many anecdotes I need to be "scientific"? Perhaps I should start a blog and I too would then have credibility?  

[Captain Fastbastard Mayhem]

I did say it was my personal experience!! However two other members of our group have tried Banting and experienced similar symptoms. Both of them have lost ground to the rest of us and have never regained their pre-Banting form. They also lost an incredibly small amount of weight.

 

I am not sure how many anecdotes I need to be "scientific"? Perhaps I should start a blog and I too would then have credibility?  

The thing is, without knowing how much you consumed, what you consumed, and how you exercised throughout those 4 months, your anecdotes will never become evidence. There's just no control. 

 

If you had catalogued each and every thing you ate, drank, ran, cycled and so on (together with HR / power / recovery etc data) then it would be applicable.

 

But until then, all we have is your assertion that you "banted" and it didn't work. That, sir, is an anecdote, and no amount of blogging will change that.