When I was doing only flats, I was 5kg thiner, all else equal. That is my rationale.

I've been 75 Kg when doing flat rides 4-5 times per week ( I was working at home so had the time to do it often ) ( for years )

80 Kg when doing it only on weekends

Last year I did mostly hills and now I am at 84-85Kg.

the rationaly is this, when doing flats, you do non-stop aerobic exercise for 1-2 hours, related to running or swiming.

when doing hills you are doing anaerobic exercise, related to weight lifting. My quads are bigger than before, but so is my belly

Calories burned is calories burned.. it doesn't matter if you are going uphill flat downhill or anything. If you are anaerobic you are still burning calories. (even more then when fully aerobic!!!)

I would argue that you burn more on a climb because you need to maintain a higher power output more constantly then on the flat. On the flat you can afford to coast every now and again on a climb you can't... until you get over the top.

Of course you may put on more muscle when climbing which weighs more then fat, but it is certainly not worse for body composition.

I think there is a sound rationale for this. Typically (of course the effect is reduced because you downshift gears) hill rides are low cadence/high torque. They strengthen and bulk up the muscles; more of the fast twitch muscles.

Flats allow high cadence and more steady pace. They use more of the oxygen breathing muscles (slow twitch); they are great for aerobic fitness but not strength-building. Moreover, being on flats might allow you to stay on the activity longer, and burn more calories.

So, for fit guys like us who can easily do a few hours of cycling, it is hills for power, and flats for weight reduction, although I doubt if the difference is too much with modern cycling techniques (27 gears, heart rate monitor etc: they have a tendency to even out the difference. I say this from common sense becos I never used one).

On the other hand if we are talking about inactive/unfit people who don't have much muscle anyway, hills might be a better option: it builds some muscles into their frame and raises the resting metabolism, perhaps regulate unhealthily high appetite levels, and thereby contributes to weight management.

Basic point: the activity to choose depends on one's current body condition and goals.

This rational is based on the rather old and not accurate principle of the "Fat Burning Zone". This has proved to be untrue. Your calories burned are proportional to heartrate (Oxygen consumption actually) which is proportional to power output. Power output tends to be higher for a given individual on a climb because of the fact that you have to lug your body weight up it. Therefore it figures that climbing by that rational is better for fat loss.

Of course if you can sustain the same power output on the flat without taking breaks, then both are equal.

Sure muscle build also is a factor.

I am 84 now and look ok, with some spots of fat to burn this season.

But I do have pictures of me some 8 years ago before starting cycling on a period where I was traveling all the time and then eatin only junk food and no sport.

I was 86Kg and I look on that pictures really overweight, with much more than the 2 kg of fat difference we are talking about. Really no point of comparison.

I do prefer to be ~80Kg though, then I am OK, when I was ~70Kg I was too thin. So this year the weight goal is to be at least stay on the 76-78K range. I have first to lose some 6Kg then.

So I am up for flat rides on weekends, during the week, I'll do hills to go to work.

Sorry I hadn't read the previous posts as I was writing my response then.

I don't entirely agree with the first statement above. If someone asks me advicee on losing weight, a pot belly, I would recommend 30 mins of steady jogging than a couple of sprints, catch your breath, sprint...routine for 30 mins.

I agree with the second statement. I had a sub-48 kilo frame a few months ago; now it is some 52-53 kg thanks to the Swiss weather and diet. I would love to have bigger quads and a bigger gut to nourish them

So, will you come with us this Sunday for the "Tour of the Zurisee" ?

If you ask a gym instuctor who has just read the books they will tell you that you must burn calories in a certain zone. This is what they have been told in their training.

Ask a sports scientist who has read the scientific literature and done the experiments in the lab and they will say calories burned is calories burned. Body composition change is much more simplistic then many people think. If you are in calorie deficit you loose weight. Approx 9kcal of deficit is 1g of fat lost. IT doesn't matter if you loose these calories at threshold or totally aerobically, providing you don't eat the calorie deficit you will lose weight.

Your absolute calorie consumption increases all the time with exercise intensity. What changes is the percentage of fuel used, not the total consumption.

Nathu, Salsa,
I would love to join you this Sat but I have committed to Patrick who posted an event starting Oerlikon, Sat morning. From the amount of sub-threads growing form here, I can sense there is a lot of bike-talk we must do...and would be nice to have a trip together.

Patrick, is it possible that we can all go for a single event rather than two different routes on the same day? I am game for either route. If the common ride doesn't work, then I come with you for the Oerlikon ride.

or we could all do both ?

Look, I am dead serious. If you think we can do, we do. And recuperate next few days...The bike bug has bitten me now

I'll try to get a racing bike for the day so I don't trail behind too much. I am the newbie here, so you guys decide and post the final event here.

what frame size you need ? I might have one

I would be up for a loop around the lake on Saturday. A 40 mile flat training ride would suit my training schedule quite well.

I don't think hill climbing makes you gain weight, except maybe in the skull size... maybe I am confusing different causes and effects...

Actually I wanted to post a "wanted" ad here, but I haven't figured out how to post a new thread so thought of doing it after meeting some of you cycling folks. And Rahul, I believe, is still in sking mood

I am 164 cms tall, with inseams (I measured my inner leg length with a book pressed up, barefoot) of about 29.5 inches. Any racing or light weight touring bike in that range should be excellent for my first group ride, before I buy anything.

I am currently using a 50 cm frame touring bike which is excellent except that is very heavy.

hey, now you are seriously misquoting someone, and I am contemplating suing you for that

It is no one's case that hill climbing is the best way to gain weight. I was only trying to say, between flats and hills, hills score higher on power, which equates to muscle gain.

Again no general statements. What applies to me, who is trying to achieve ideal mass from below, may not hold for Salsa who is reaching his ideal from above. On balance, I think I should be doing more hills, and Salsa, flats...for whatever negligible difference that makes.

And what applies to weekend riders like us won't apply to pros...

You'd be surprised!

Wasn't replying or quoting anyone in particular Just wanted to post empirical evidence that hill climbing would seem to make you thin! I do not know much about the biological aspects of cycling so can't comment on that much.

Nor do I
Just keeping the traffic volumes high here, hoping it translates into more people for the weekend.

Think it's more a chicken and egg thing. Climbers tend to be very light and lean. I don't think it's necessarily a case that climbing makes them that way (but it sure doesn't harm it), but more their physique is suited to going uphill. High power/weight ratio. When we talk about pro's we talk about people who have adapted the phenotype pretty much as far as it will go. Their training is totally designed to make them as suited to their discipline as possible, but their physiology would have been somewhat geared towards that from the start anyway.

Having said that, the principles of adaptation to training are the same for all of us. It's just the pro's can recover better from high training loads.

An example I've used before, is that many pure timetrialists go to the mountains to train, very few pure climbers do motorpacing or time trial training. (One exception of Micheal Rassmussen after he f**ked up a time trial in the tour a few years back).