Slimming down before a race

[Jwolf]

Also there are certain nutrients we need daily that our body can't store well (e.g. water soluble vitamins). Without them you'll be compromising some physiological processes.

[Wu wei]

Losing weight in general slows metabolism. But why is it a bad thing to have a lower resting HR?

Not sure I follow. Are you confusing metabolism with HR?

Metabolism is the set of processes that help maintain life; these processes generally fall into two categories: catabolism and anabolism. Catabolism is the break down of substances for energy, an example of catabolism is the breakdown of glucose into ATP. Anabolism is the formation of substances that are needed within the body, an example of anabolism is the formation of muscle proteins from amino acids.

[Spirit Unleashed]

Losing weight in general slows metabolism. But why is it a bad thing to have a lower resting HR?

Not sure I follow. Are you confusing metabolism with HR?

Metabolism is the set of processes that help maintain life; these processes generally fall into two categories: catabolism and anabolism. Catabolism is the break down of substances for energy, an example of catabolism is the breakdown of glucose into ATP. Anabolism is the formation of substances that are needed within the body, an example of anabolism is the formation of muscle proteins from amino acids.

So, fasting could use up your glycogen store, release water so you think you lost weight, then have no energy for running?

[jamix]

Measuring your RMR is hard to do, so I just measured my HR. Any lifestyle that causes you to lose weight will cause similar changes.

[jamix]

Losing weight in general slows metabolism. But why is it a bad thing to have a lower resting HR?

Not sure I follow. Are you confusing metabolism with HR?

Metabolism is the set of processes that help maintain life; these processes generally fall into two categories: catabolism and anabolism. Catabolism is the break down of substances for energy, an example of catabolism is the breakdown of glucose into ATP. Anabolism is the formation of substances that are needed within the body, an example of anabolism is the formation of muscle proteins from amino acids.

So, fasting could use up your glycogen store, release water so you think you lost weight, then have no energy for running?

You shouldn't train hard while you fast. I never fasted for more than 24 hours.

[Spirit Unleashed]

So, fasting could use up your glycogen store, release water so you think you lost weight, then have no energy for running?

You shouldn't train hard while you fast. I never fasted for more than 24 hours.

You don't have to train to use up glycogen while fasting. Its the first fuel on the list and your body will use fuel just to sit around.

[jamix]

So, fasting could use up your glycogen store, release water so you think you lost weight, then have no energy for running?

You shouldn't train hard while you fast. I never fasted for more than 24 hours.

You don't have to train to use up glycogen while fasting. Its the first fuel on the list and your body will use fuel just to sit around.

Sure but in the long run you won't necessarily be depleted of glucose. When I ran 19:27 / 5 km in November I had only lost 1.5 lbs and ran the race during a non-fasting period.

[Jwolf]

The thing is that if your HR goes down while you're fasting, it's not the same type of positive, lasting effect you get from training. Your heart slows down because there is less available fuel and your body is conserving energy (i.e., slower metabolism). If you try to train like that you'll be forced to go more slowly.

Some people do purposely try to train on depleted glycogen to mimic what the body does in extensive endurance events. But I'm not sure that cycles on and off of fasting is all that effective for someone trying to lose weight and train for speed.

[jamix]

The thing is that if your HR goes down while you're fasting, it's not the same type of positive, lasting effect you get from training. Your heart slows down because there is less available fuel and your body is conserving energy (i.e., slower metabolism). If you try to train like that you'll be forced to go more slowly.

Some people do purposely try to train on depleted glycogen to mimic what the body does in extensive endurance events. But I'm not sure that cycles on and off of fasting is all that effective for someone trying to lose weight and train for speed.

You can still train for speed, but your training in general will be a little lacking so you shouldn't look for PBs. As reference, by the time it was late-December, my tempo run slowed such that I was only able to run a 19:33 4.8 km even though I had lost about 5-6 lbs. I was running during a non-fasting day too.

PS: This is unrelated to this topic. On a couple of occasions I ran over 10 miles after fasting for over 22 hours. I experienced some pleasant sensations the following day and was unusually happy.

[mcshame]

Reading through the responses here just makes me want to go on one of those 40-day juice fasts .

Personally though, I have found that attempting to improve time through diet/weight loss is unsuccessful. Last March I weighed approximately 20 lbs less than I do now and I only managed to run a 41:51 10 km. Since then I have run faster despite being so much heavier.

All this talk of fasting got me scratching my head on what on earth are we talking about. I went back and found this post, you were talking about weight loss and that you did not have increased performance. Now I understand why.

[Agent Provocateur]

Intermittent fasting is perfectly healthy. Intermittent fasting does not slow your metabolism. It's the weight loss and food industries that have made us believe that we have to eat constantly.

You can still exercise while fasting, but I don't recommend doing endurance training while fasting. Also, in response to something I read on page 1 (I think), losing weight will not digest your muscle if you are losing fat... which is what you will lose if you use intermittent fasting properly.

See http://www.eatstopeat.com for more information.

[Spirit Unleashed]

My most successful and long term weight loss and stabilization came after I learned to stay on a permanent "diet." I used to fast but found my weight jumping around much more than if I just faced the fact of eating just the right amount.

[jamix]

Reading through the responses here just makes me want to go on one of those 40-day juice fasts .

Personally though, I have found that attempting to improve time through diet/weight loss is unsuccessful. Last March I weighed approximately 20 lbs less than I do now and I only managed to run a 41:51 10 km. Since then I have run faster despite being so much heavier.

All this talk of fasting got me scratching my head on what on earth are we talking about. I went back and found this post, you were talking about weight loss and that you did not have increased performance. Now I understand why.

Yep....I wasn't following an IF regime at the time though.

Agent P....

I'm sure any regime that causes weight loss will cause a slowing of the metabolism. I didn't measure mine directly but my HR was always lower on my fasting days. Although muscle wasting shouldn't occur, muscle glycogen stores may still be lower.

HPS....

Keep in mind you followed a different regime than I did. You went on a Juice Fasts, yes?

[Wu wei]

It's the weight loss and food industries that have made us believe that we have to eat constantly.

No, it's called hunger. It's our bodies defense mechanism telling us to refuel.

You can still exercise while fasting, but I don't recommend doing endurance training while fasting.

Yup.

[Agent Provocateur]

It's the weight loss and food industries that have made us believe that we have to eat constantly.

No, it's called hunger. It's our bodies defense mechanism telling us to refuel.

Your body can "learn" to feel hungry at certain times. It's a Pavlovian response. If a person experiences REAL hunger every few hours, they're probably experiencing hyper-metabolism, a sign of serious disease.

Most people can't tell between real hunger and perceived hunger.

[mcshame]

Intermittent fasting is perfectly healthy. Intermittent fasting does not slow your metabolism. It's the weight loss and food industries that have made us believe that we have to eat constantly.

You can still exercise while fasting, but I don't recommend doing endurance training while fasting. Also, in response to something I read on page 1 (I think), losing weight will not digest your muscle if you are losing fat... which is what you will lose if you use intermittent fasting properly.

See http://www.eatstopeat.com for more information.

I'm not going to challenge your belief but I pretty sure you can add government to the list of those telling us to eat our meals right in our schools (canadian food guide).

Not alot of information at the site, Looks like all the other weight loss fixes, did this and now I nearly have a 6 pack... There is no sure way for all people, different things work for different people, experiment of one.

Edit: well, I did challenge your belief a little bit

[Jwolf]

It's the weight loss and food industries that have made us believe that we have to eat constantly.

No, it's called hunger. It's our bodies defense mechanism telling us to refuel.

Your body can "learn" to feel hungry at certain times. It's a Pavlovian response. If a person experiences REAL hunger every few hours, they're probably experiencing hyper-metabolism, a sign of serious disease.

Most people can't tell between real hunger and perceived hunger.

I agree with this- hunger is largely a learned response. It rarely means that we need food. Eta: lorne- we're talking about healthy adults here- not children.

That said, fasting will cause performance to suffer at least temporarily. I'm just not sure how intermittent fasting will really allow one to train optimally. But it might help those who want to lose weight quickly.

[deerdree]

That said, fasting will cause performance to suffer at least temporarily. I'm just not sure how intermittent fasting will really allow one to train optimally.

that's what i'm thinking, too. a quick search of intermittent fasting on pubmed brings up studies that suggest that 1) intermittent calorie restriction is as effective as continuous calorie restriction for weight loss in overweight/obese individuals but 2) it can impair recovery from exercise.

eg:

Br J Sports Med. 2010 Jun;44(7):502-8. Epub 2010 May 10.
Fasting and recovery from exercise.
Burke L.

Australian Institute of Sport, PO Box 176, Belconnen ACT 2616, Australia. louise.burke@ausport.gov.au
Abstract
Recovery after strenuous exercise involves processes that are dependent on fluid and food intake. Current sports nutrition guidelines provide recommendations for the quantity and timing of consumption of nutrients to optimise recovery issues such as refuelling, rehydration and protein synthesis for repair and adaptation. Recovery of immune and antioxidant systems is important but less well documented. In some cases, there is little effective recovery until nutrients are supplied, while in others, the stimulus for recovery is strongest in the period immediately after exercise. Lack of appropriate nutritional support will reduce adaption to exercise and impair preparation for future bouts. Ramadan represents a special case of intermittent fasting undertaken by many athletes during periods of training as well as important competitive events. The avoidance of fluid and food intake from sunrise to sundown involves prolonged periods without intake of nutrients, inflexibility with the timing of eating and drinking over the day and around an exercise session, and changes to usual dietary choices due to the special foods involved with various rituals. These outcomes will all challenge the athlete's ability to recover optimally between exercise sessions undertaken during the fast or from day to day.

[ultraslacker]

That said, fasting will cause performance to suffer at least temporarily. I'm just not sure how intermittent fasting will really allow one to train optimally. But it might help those who want to lose weight quickly.

lose weight quickly? jamix only lost 5lb in 13 weeks. I can think of much healthier, more effective, and training-friendly ways to lose weight.

[Jwolf]

I said "might". I can guess that some people overcompensate on their non-fasting days that it would make it less than successful. I also agree that there are better ways to lose weight- then again, it's not that easy to lose five pounds in 13 weeks if you are close to your ideal weight.

[mcshame]

Jen, the Canadian food guide applies to children and adults, and eating behavior is very difficult to change. So I disagree with you, how we learn to eat as children very much affects our eating habits as adults.

[Jwolf]

Jen, the Canadian food guide applies to children and adults, and eating behavior is very difficult to change. So I disagree with you, how we learn to eat as children very much affects our eating habits as adults.

What i mean is- hunger is a learned response for adults. For children too, but they DO need to eat more often than we do as they are growing.

Its actually what you just said - eating BEHAVIOR. We do train our bodies to be "hungry" at certain times of the day, but that doesn't necessarily mean we need the calories.

For example- snacking at night. You'll feel hungry at night if you are used to snacking at night. But you don't really need those calories if you are overweight. If you want to lose weight and you decide to cut late-night snacking, you can. It takes time to retrain yourself, but you can-- and you will feel hungry at first as you start to change the behavior. But after a few weeks or so of not snacking, you won't feel hungry anymore.

[ROW]