I’ve been looking at some you tube videos about how to maximise fat loss and note that the advise is to exercise at 60-70% of maximum heart rate. The body also holds around 2,000 calories of carbohydrates in the liver and muscles.

Anyone know if we have to use up the 2,000 calories of carbohydrates before the fat stores are used, or by training at a lower intensity, fat is used as the primary fuel from the start of the exercise, leaving the carbohydrates in the liver/muscles; therefore after exercising we don’t get these cravings for carbohydrates?

Simplistic answer: If you don’t refuel adequately and leave it until the energy in your liver and blood glycogen is consumed you’ll get the effect known as bonk, hunger knock or “the wall” in running parlance. How long this takes depends strongly on the individual, how well they have developed their ‘economy’ and the intensity of exercise – but typically you’ve got 1-2 hours before you run out. Topping-up your energy reserves regularly through energy drinks and food so as not to overload your digestive system (diverting blood flow from the muscles) and keeping your glycogen stores topped up is key, as well as staying hydrated and maintaining your electrolytes. Fortunately, there is lots of advise available and conveniently packaged food and drink to make life easier. There are also advocates of ketogenic diets where you train your body to run on fats not sugars – quite a complex subject, but from knowing people who’ve done this, bonked on every ride for months on end!

Anyone know if we have to use up the 2,000 calories of carbohydrates before the fat stores are used, or by training at a lower intensity, fat is used as the primary fuel from the start of the exercise, leaving the carbohydrates in the liver/muscles; therefore after exercising we don’t get these cravings for carbohydrates?

The latter, simply.

I did keto (<20g/carbs/day) for 18 months. You lose your top 15% of power (when you have to burn anaerobically you need to burn carbs) but can ride all day on zero food and never even get hungry (as you’ve tens of thousands of calories available in your gut).

But if you don’t want to do a very restricted diet – low intensity long rides. Eat proper balanced meals and maintain a small caloric restriction over time.

If you are disciplined you will lose weight.

maintain a small caloric restriction over time.

This.

It may be through restricting the foods you eat, eg paleo, keto, vegan, atkins.

It may be through restricting the time window, eg intermittent fasting.

It would may be through the amount, eg whole foods, weight watchers, weighing food.

Pick whichever suits you best to alter your eating habits.

For most people, changing some of the foods helps. For example, replace liquid calories and refined sugars/flours with non starchy vegetables should do it for 90% of people.

Keto here too. Over 30KG lost since mid Feb. Initially I bonked, but after a few weeks I became fat adapted and it no longer happens. I can head out for a ride or run early in the day and not have to worry about eating first or refuelling during the ride. I’m not an athlete pushing for every last watt though.
I tried simple calorie restriction but failed because I always felt hungry. On Keto I don’t feel hungry even though I’m on under 1800 calories per day.
It is restrictive; I really miss bananas, apples and melon, although I do eat strawberries and raspberries most days (with a good sized helping of double cream). Oh and chocolate. I really miss chocolate. Which is probably why I was fat…

Over 30KG lost since mid Feb. Initially I bonked, but after a few weeks I became fat adapted and it no longer happens.

Or you just got fitter/learnt to ride slower

I’m definitely not riding slower and I am fitter, but I’m on under 20g of carbs per day so my fuel is not coming from that.

Thanks, 30kg loss is impressive!!

When I ride anaerobically, I then crave carbs after the ride.

If by training at an easier intensity, I burn fat from the go, and possibly avoid the cravings for the carbs, I can then loose some bodyfat.

I’m looking more as a fat loss thing than riding with a group/bonking if the intensity is high.

I’m definitely not riding slower and I am fitter

No you would almost certainly be faster if 30kg lighter, you could well be putting less effort in and going slower.

If by training at an easier intensity, I burn fat from the go, and possibly avoid the cravings for the carbs, I can then loose some bodyfat.

Just ride harder and eat appropriately no need to over think it or look for the easy way.

Low intensity low O2 exercise will burn fat first. Fat is the preferred energy store to get used first but isn’t as quick and easy as carbs.

Low intensity low O2 exercise will burn fat first

Thats true but exercising harder will burn more fat and for longer after you have stopped exercising.

No you would almost certainly be faster if 30kg lighter, you could well be putting less effort in and going slower.

I’m definitely not going slower, but you carry on questioning me if it makes you happy.
And I lost that weight by going on a Keto diet, which I know you are opposed to.

When I ride anaerobically, I then crave carbs after the ride.

I have either bacon and eggs or a dirty-keto protein bar after a ride, mainly because it’s usually lunch time.

I’m definitely not going slower,

As I said I would be astonished if you werent faster if 30kg lighter.

And I lost that weight by going on a Keto diet, which I know you are opposed to.

No I am just opposed to bullshit.

I’m expect you think all that bacon is really good for you too.

Show me the bullshit or STFU. Back up your claims about my diet with some facts.

I track all my food and today was under 16g of net carbs (I don’t include fibre in my carb count). No bacon today though. Or yesterday for that matter. There’ll be some tomorrow though. It’s yummy.

Here’s a before and after pic. The before pic would have been after several months of failed calorie control dieting, the after is the result of Keto.

by I tried simple calorie restriction

Keto is calorie restriction. You restrict them by cutting out carbs.

Unless you’re rewriting the laws of thermodynamics then you’re losing weight through exactly what you think you’re avoiding:calorie restriction.

You’re just calling it something else.

Well done on the weight loss and I’m glad you’ve found a method of cutting calories that works for you!

Thats true but exercising harder will burn more fat and for longer after you have stopped exercising.

That’s only partially true.

There are a lot of effects that you can trigger by doing various types of exercise, and your body will respond differently. It also depends on what you’ve been doing up til now. For many people, doing short high intensity workouts is better for fat loss. But as cyclists we are well used to battering ourselves for two or three hours which for me at least places too great a load on my system to restrict calories – even if I feel like it’s just a normal hard ride. Calorie restriction and hard riding means I feel like absolute crap, I don’t recover, and even my BMR reduces. If I eat to recover then I don’t lose weight. But I do get much faster and stronger. There are probably a few reasons for this – terrain is steep around here so at my weight if I don’t dig in then I might as well walk up, which I’m not going to do; I also am naturally predisposed to hard efforts so it’s what my legs want to do. Plus there’s adaptation – what worked for me ten years ago when I first tried it doesn’t work any more.

Start with the basic advice first, then if you struggle with that you need to adjust parameters to figure out why you’re struggling.

No I am just opposed to bullshit.

I too am opposed to bullshit, being critically minded and having a science degree, however you are dismissing a lot of science with your cynicism I think. It’s well documented that whilst the basic principles of reducing calorie intake and doing more exercise hold true for MOST people, there are lots of people who struggle, and it’s not simply a case of these people greedy little piggies with no willpower and being in denial about it.

I too am opposed to bullshit, being critically minded and having a science degree, however you are dismissing a lot of science with your cynicism I think. It’s well documented that whilst the basic principles of reducing calorie intake and doing more exercise hold true for MOST people, there are lots of people who struggle, and it’s not simply a case of these people greedy little piggies with no willpower and being in denial about it.

This, i had this argument with AA before.  I lost 8kg over 4 months on keto.  Since then I’ve introduced more carbs as my training has changed.   My calorific deficit is at the status quo yet my weight started to rise in June/July as I went quite carb heavy.  I’ve reduced the carbs – same weekly deficit – and deferred to more protein and my weight’s started to reduce again.  FWIW I have an average 2100 cal deficit per week regardless of my proportionate macros.    I’ve struggled with weight fluctuation in all sports through my lifetime being 14.5 stone and muscular 25 years ago, 13 stone and fat 15 years ago,  now 11.5 stone and slim mtb but not road shaped now. I’ve always wondered what trigged my weight going up and down, now I’ve learned I’m sensitive to carbs in this matter.

Keto is calorie restriction

Keto is based on exactly what I wrote above re energy sources. If you restrict your sugar intake the body will use fat as an energy source.

If you take in sugar that stimulates insulin production which stimulates lipogenesis and a decrease in fatty acid oxidation. No sugar intake means the opposite.

You still have to use more energy than you take in obviously.

Show me the bullshit or STFU.

First law of thermodynamics

My calorific deficit is at the status quo yet my weight started to rise in June/July as I went quite carb heavy

How do you know you are measuring the calories correctly? How do you know your werent pushing harder and building muscle?

A few very fat people going on a diet and losing weight doesnt mean the type of diet is a magic bullet or that they have magically found that low intensity exercise causes greater calorie loss by some magic. True it may help at the margins with feeling full for longer, butvthe basic principle of eat well and exercise more will do it for almost everyone

Scanning and weighing the food that I eat.  I’m not arguing about it again, I know what’s working for me and the effects of changing my % macros are a constant and becoming predictable now.

If I eat “normally” 1800 Calories is unsustainable as I constantly feel hungry. Depending on what I eat, on some days 1500 is enough on Keto to stop the hunger pangs. Keto as a way of eating has enabled me to cut my calorie intake and lose weight in a way I’ve never managed before. I’d never make it through a day’s ride without breakfast and a snack before either.
Once I reach my target weight I’ll be able to eat more to sustain, but I’m actually enjoying the foods I eat now.
Of course I miss chocolate, bread, chips, pasta, etc but judging by the noise, smells and state of my turds they weren’t doing me any good at all.
My cholesterol was at 4.something before I started and as soon as I can get an appointment for a non-emergency I’ll get it checked again. My blood pressure is down from hypertensive to normal too.

You can piss and moan all you want. I’m happy with what I’m doing and the results I’ve got doing it.

First law of thermodynamics

…says you can get all your calorie needs by drinking 300ml of sunflower oil

But I suspect rapid (and somewhat alarming) weight loss would be the result of that as a diet.

I’m happy with what I’m doing and the results I’ve got doing it.

And so you should be, your pics show a remarkable transformation and as long as you are healthy you’ve  achieved something really quite commendable.

Here’s a before and after pic. 

Bloody hell, that’s awesome! I’m off to look up keto diets… 🙂

Try and apply thermodynamics to a petrol car with diesel in the tank. There is some moronic BS on this thread.
Burn anyones turds and there is energy in them. Where does that come from?
kryton doomaniac et al, ignore the haterz. It is your body.

I think you’re missing the point AA, eliminating carbs in the keto diet stabilizes your blood sugar/insulin levels so when you restrict calories you don’t get the severe hunger pangs so it is a lot easier to maintain reduced calories and therefore lose weight.

Well done to doomaniac – glad you found a way to manage your weight that works for you, and that sounds sustainable in the long term. The worldwide multi billion pound weight loss industry exists solely because of the fact that it is so hard to do what you’ve done.

Try and apply thermodynamics to a petrol car with diesel in the tank. There is some moronic BS on this thread.

And what you posted is pretty much it.

Actual no, I read your second sentence thats even better.

Burn anyones turds and there is energy in them

says you can get all your calorie needs by drinking 300ml of sunflower oil

But I suspect rapid (and somewhat alarming) weight loss would be the result of that as a diet.

Correct, a balanced diet needs things other than just energy, although wouldnt sunflower oil only be keto, certainly low carb!!

Unless you’re rewriting the laws of thermodynamics then you’re losing weight through exactly what you think you’re avoiding:calorie restriction.

Which particular law are you talking about? When talking about nutrition and human metabolism the 2nd law is probably the most pertinent: Entropy. This law emphasises that all real engines – in fact all processes in the real world are inherently inefficient. The heat generated in the processing of food. The measured thermic effect of feeding of different macronutrients (protein, carb or fat) is different.

Calories are a measure of energy.In physics the definition of a calorie is given as the amount of heat required to raise the temperature of water by 1 degree. Calories refer to a chemical reaction not the food itself

Once people realise that not all calories are equal and that human metabolism is based on hormones and feedback systems you start to learn why keto, intermittent fasting and atkins all work on helping you lose fat/use fat a a fuel source. They play to how hormones and this feedback system works in the body. The main hormones at play at insulin (controls fat utilisation and fat storage), leptin (controls hunger ) and grehlin (stimulates appetite). it’s simple really.. if you reduce the amount of insulin in the body you will utilise more fat as a fuel source and reduce the amount of fat stored. Hunger is also reduced as the signalling works better. Higher GI carbs effectively bypass this system and doesn’t tell the body you are full. Anyone can try this . try eating 3-4000 calories from cakes or doughnuts and 3-4000 calories from fat or protein. The effect will be different

it’s also worth looking at the different metabolic pathways when eating either protein,carbs or fat. Going keto you introduce gluconeogenesis: the process of creating glucose from non carboyhydrate sources. This process from a an energy point of view is very expensive.

This book goes into a lot of detail about human metabolism and the science behind low carbohydrate diets.

I don’t have a science degree, but it seems perfectly clear to me that there’s a little more to it than simple thermodynamics.
Humans differ from an engine in that they have emotions and produce hormones which screw with the simple in/out equations.

This is interesting.

No one seems to discount the effects of testosterone on the body. Like insulin it’s an anabolic hormone. It increases protein synthesis, and increases muscle mass and strength amoungst other things.

Also worth bearing in mind that exercise, especially intense exercise improves insulin sensitivity. it isn’t just the use of energy its stopping the pronounced effects of insulin in the body – ie the effect of fat storage
https://diabetes.diabetesjournals.org/content/51/suppl_1/S271

Whats funny is that some of those on here backing keto diet even admit it led to them consuming less calories, whilst others dont confusing. Whilst the keto diet may work for some its not due to increased fat burning in low intensity exercise as the op was asking about. The discussion has been derailled into two conflicting parts, how to burn more fat (high intensity exercise mixed with recovery is the established view)and how to lose weight (eat less exercise more and it is in the eating less that a keto diet may help).

Also worth bearing in mind that exercise, especially intense exercise improves insulin sensitivity

Would also increase testosterone wouldnt it?

What I was going to post has already been posted.

Citing thermodynamics is pointless. Human bodies are way way more complicated than that. We all know people who stay skinny regardless of how much they eat or what exercise they do – they are not that uncommon. That alone should demonstrate that the simple thermodynamic equation does not hold true and there is a lot more going on.

First law of thermodynamics

What about the other laws of thermodynamics? If you look into the study of thermodynamics you’ll realise why its the second law that is more pratical as it explains how energy is used to do work and how chemical reactions occur.

No real world energy system is 100% efficient. When talking about food if you’re going to carry out all the work, physical and chemical using the energy from food then you can’t do it perfectly efficiently. Some part of that energy MUST be wasted. If you are trying to lose weight the job of synthesizing and storing fat might be one that you want to run as inefficiently as possible

Whilst the keto diet may work for some its not due to increased fat burning in low intensity exercise as the op was asking about.

What is it then? Are you disputing how human metabolism works and the effect of hormones in the body? Is it not conceivable that different energy pathway systems are at play depending the macronutrient composition of food.

Do you still believe all calories are equal?

What is it then?

They are able to eat less would be by far the biggest impact.

Is it not conceivable that different energy pathway systems are at play depending the macronutrient composition of food

Respiration is respiration. Protein is absorbed as amino acids and feeds into cellular respiration by being converted to glucose or pyruvate AFAIK. Net result is the same number of ATP’s

Do you still believe all calories are equal?

Of course they are, that like asking if all m are equal.