Question about fat burning

[dr0832]

When you wake up, eat for instance an omlete made with whole eggs, avacado and cheese, and then immediately go run at a medium pace, what does your body use for fuel? Obviously fat is digested slow so you couldn't possibly be buring the food you just finished eating.

 

[wtlftr]

Question, why would you eat right before a run? How far are you running, what mph are you running, what did you eat in the previous days, have you currently been running and training?These should be answered first for a more complete answer to your question

 

[psychedout]

If your doing your cardio first thing in the morning, it is best on an empty stomach.

 

[juve]

I concur to replies above.
If you want your body to utilize fat as fuel VO2 max should be kept very low, and you shouldn't consume any food prior to cardio since your body has already an abundance of free fatty acids produced ready to be burn up..
If you opt for more intense cardio then fats+protein are not an optimal energy solution - as VO2 max increases body shifts from lypolisys as a source of energy to glycogen. Since you did not consume any carbs it will go for the next best thing - gluconeogenesis ie converting your proteins to sugars

 

[dr0832]

well I'm on ckd so I was trying to deplete liver glycogen because yesterday and the day before I had my carb up which ended at noontime yesterday. So from noon on yesterday I ate just fat and pro. I ran at about 5mph for 35 minutes. I don't usually eat before but today my mother had already made food so I couldn't not eat it. I was just curious what happens in a situation like this since it obviously impossible to use food that has just begun the digestion proscess.

 

[Stryc-9]

On CKD? I'd wager you're burning stored glycogen from your carb-up period. Consuming a meal of fat and protein (assuming protein intake is modest) won't prevent you from getting back into ketosis, if that's what you're asking.

There will be a moderate insulin release from the ingested protein - but nothing that will hinder progress. I'd be more worried about cramping up while running with that much food in my gut.

 

[bran987]

I concur to replies above.
If you want your body to utilize fat as fuel VO2 max should be kept very low, and you shouldn't consume any food prior to cardio since your body has already an abundance of free fatty acids produced ready to be burn up..
If you opt for more intense cardio then fats+protein are not an optimal energy solution - as VO2 max increases body shifts from lypolisys as a source of energy to glycogen. Since you did not consume any carbs it will go for the next best thing - gluconeogenesis ie converting your proteins to sugars

I have 3 questions..

Can you explain to me what it means when you say "your body already has an abundance of free fatty acids ready to be burned up"? What do you mean?

Also.. would this absence of carbs before intense cardio resulting in gluconeogenesis also apply to weightlifting?

Also.. when you say that during intense cardio your body shifts from lipolisys to glycogen for energy.. when it shifts to glycogen will it use recently ingested carbs first.. or carbs stored up in your muscles instead.. in other words if I already have carbs stored up in me do I need to eat MORE before I workout or will my stored carbs be sufficient for energy during the workout.

sorry.. I'm not sure if what I asked was clear.. I'm trying to learn.

 

[JKurz1]

what if you have VERY little carbs in your system and do cardio? Do you have to replensih afterwards?

 

[juve]

Can you explain to me what it means when you say "your body already has an abundance of free fatty acids ready to be burned up"? What do you mean?

Also.. would this absence of carbs before intense cardio resulting in gluconeogenesis also apply to weightlifting?

Also.. when you say that during intense cardio your body shifts from lipolisys to glycogen for energy.. when it shifts to glycogen will it use recently ingested carbs first.. or carbs stored up in your muscles instead.. in other words if I already have carbs stored up in me do I need to eat MORE before I workout or will my stored carbs be sufficient for energy during the workout.

1) When you wake up blood plasma is satiated with de-esterified free fatty acids from overnight fasting to keep your body functioning during sleep. If you consume a meal this process will stop, however if you opt for >light< increase in activity (cardio) you can prolong and augment this process. But don't overdo it, because even at a constant stead low pace there's a set point beyond which no more ketones will be produced for fuel, but rather proteins (this should be intuitive, after all it's been about 6+ hours after last meal)
2)Yes/No. Depends on intensity of weightlifting. If you do high vol low weight training it will be aerobic - fat=fuel.
High intensity weightlifting is anaerobic excercise - it needs glucose for fuel. No glucose=>gluconeogenesis
3)Carbs are either stored in liver glycogen, muscle glycogen, adipocytes or constitute a fraction blood plasma. Those in blood will be used up first, followed by muscle glycogen, then liver, then adipocytes (that's why when dieting down you better stick to clean refeeds because depletion and de-esterifying of fat cells will come as the last resort of body to produce energy). Generally studies have shown that a consumption of low fat + mod pro + mod/high carb meal will yield higher endurance and higher potential for VO2max output, but most people are not concerned with that since they don't compete. So I'd say as long as you're capable of performing at peak intensity for short duration repeatedly (sprints, HIIT) you may or may not opt for a carb meal prior. To measure this simply observe fluctuation in your endurance/fatigue - if onset of fatigue is fast it means lactate levels are rising meaning pyruvate is being used to break down aminos (byproduct of pyruvate breakdown is lactic acid) to be used for fuel which constitutes catabolism.