Fat burning zones, a question

Swannie

Alex_Simmons/RST wrote:

Metabolism will slow with a long term large calorie deficit, and cycling performance can be degraded.

What he said.

ut_och_cykla

guinea wrote:

Every human is diferent. Also, your body constantly adjusts and changes how it burns fats.

For my lifestyle (without cycling) I should eat 2350 cals a day to maintain weight. I should also eat any calories I burn off through additional exercise.

For those who don't know there are 3500 cals in 1lb of fat. I eat 1600 cals a day so that I lose about 1.5lbs a week. I have stuck to this religiously for the past coule of months. n the same time I have also an exercise deficit of 29K calories.

I should have lost 20+ pounds, but instead have lost about 2lbs. My body has decided it doesn't want to lose any more fat and is running so efficiently that it can run on 1600 calories a day while I cycle 250 miles a week.

Guinea. How do know your exercise deficit is 23000 calories? - thats about 46 hours at 500kcal - an average to good 'burn' figure for many. perhaps you haven't really burnt that much - at 300kcal/hour 46 hours is only 13800 which on a daily basis over 2 months is just 230 kcal a day - easy to nibble without realising. Perhaps you are already quite thin too - trying to go below an already low BMI/fat % is very difficult as most people naturally react to starvation.
There is anecdotal evidence that eating too little over time is adapted to (ie POWs etc). Yes they got very thin but with a trickle of food they stayed alive and worked ...Whether this applies to people at a healthy weight Ive no idea.
As Alex says eating too little and undertraining because your muscles are under/malnourished is probabaly more 'harmful' than being a oiund or two overweight!

guinea

I guess I should come clean with a little more of my medical history. I am 13 stones (82kg) or so and am 6'2" (187cm). I have a healthy BMI but would like to lose a little more to help me up the hills.

A year ago I weighed almost double what I am now. I lost nearly half my body weight on a Very Low Calorie Diet. I took a dive into a very extreme diet. I'm kind of an all or nothing person and the strict regieme of eating nothing other than what I was given suited me.

Now that I am a healthy weight the hard work starts. Statistics show that 94-98% of people who lose 100lbs or more put it back on in three years, I do not want to be in that statistic.

However, my metabolism is slow. Dead slow.

I accurately (obsessively?) mark down every single calorie and log all exercise I do. I use www.weightlossresources.co.uk and www.mapmyride.com to store and work out my calories burnt. This is as reliable as I can be.

I am cycling 250 miles a week at the moment and my performance in constantly increasing. I am building up the muscle mass lost through the weight loss programme and trying to get my metabolism faster.

It can take 9 months for someone who loses a lot of weight to get back to a normal metabolism. Mostly this is due to the fact that there is less muscle to burn the calories.

If I slip off my diet, as I sometimes do, I put on weight at an alarming rate. If I have two days of calories around 4k I can put on 9lbs. Most of this weight is water as I replace the fat around my kidneys/liver that likes to store water. This is burnt off in two days of exercise but it put me above my healthy BMI target and reminds me I have to go lower before I can add the glycogen store back.

However, as you can see it's going to be a bloody hard job for me to lose the weight. If I go back to eating I will balloon very quickly, but the dieting just prolongs the low metabolism. Ho hum, not a very good Catch 22 situation to be in. Over the next month or so I will be adding 100 cals a day to my diet every week to see how that affects my weight.

All I can do is keep the exercise up and be happy that I am at least educated enough to realise what's going on with my body. I guess the reason most others fail is they simply don't understand the maths behind the problem.

Alex_Simmons/RST

If you keep up with the exercise, then you have a significant headstart over others who returned to an obese state. It sounds like you enjoy riding your bike which is great

I would strongly suggest not to become obsessed with losing "the last few pounds". In cycling, once you have reached a healthy weight range (which you have), it is more important to focus on improving your power output than attempting to lose weight.

Now while you have managed to monitor your intake carefully, monitoring your caloric output is only a guesstimation using the tools you mentioned.

ut_och_cykla

Congrats on the weight loss and taking responsibility over your own health. But like Alex says don't obsess! if your BMI is ok, stick there, train hard. Do some of your 250 miles a week (10%?) at as brisk a pace as you can manage. Also consider taking up some fairly concientious weight training to stimulate muscle growth. With careful planning this could complement your other exercise - just concentrate on multiple muscle exercises - not just sit ups and biceps!!