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The liver storing ability to store glycogen is one of the reasons many fitness enthusiasts would avoid (or not) fructose. From what I have heard fructose often

The liver storing ability to store glycogen is one of the reasons many fitness enthusiasts would avoid (or not) fructose. From what I have heard fructose often gets broken down in the liver and thus often gets stored there (I'm probably missing a whole bunch here so assume I am wrong). Because of this various athletes and bodybuilders would use fructose to either gain weight or rapidly fill carb stores but only would do so sparingly (ie during carb refilling during a ketogenic diet).

ibejoeb 9y ago
Robert Lustig does a good talk about sugar metabolism in "Sugar: The Bitter Truth": https://www.youtube.com/watch?v=dBnniua6-oM https://www.youtube.com/watch?v=dBnniua6-oM Also, "The Trouble with Fructose": https://www.youtube.com/watch?v=Yh4JBXaKnmA https://www.youtube.com/watch?v=Yh4JBXaKnmA Despite the baity titles, it's a good talk with real biochemistry. Edit: better video added up top
- agumonkey 9y ago
  Lustig is not a joke, but I'd love to have other wise point of view on the matter.
  - deegles 9y ago
    What would this other point of view show? I don't see how there can be alternative opinions on this, metabolism isn't that different between humans. I guess you could argue that he didn't reach the correct conclusion, but that's different point.
    - wutbrodo 9y ago
      Googling 'Lustig criticism' gives you a good place to start. Though with nutritional science, everything is so far from consensus (and when there is a consensus, it's 20 years behind the science) that you should treat this as a jumping-off point to read the literature instead of an authoritative rebuttal. http://www.alanaragonblog.com/2010/01/29/the-bitter-truth-about-fructose-alarmism/ http://www.alanaragonblog.com/2010/01/29/the-bitter-truth-ab... There's a section about halfway down where he discusses Lustig's claims that things like HFCS are metabolized differently and negatively.
    - agumonkey 9y ago
      Because I'm not a doctor or a biologist, so I need a few counterpoints as checks in order not to be blinded. It's just a quick check valve while I read more about the subject.
  - ibejoeb 9y ago
    Me too. I know this is essentially his gig now, but I haven't seen anyone attack the science. If there's a reasonable refutation out there, I'm all ears.
    - jeffdavis 9y ago
      In his video he talks about the amount of salt in Coca Cola like it's part of some grand conspiracy. Coke has very little salt, so it makes me question a lot of his other claims.
      - crottypeter 9y ago
        I'm gonna echo GP >I haven't seen anyone attack the science. If there's a reasonable refutation out there, I'm all ears.
    - imcoconut 9y ago
      Ray Peat addresses the science better than anyone I've read. He's a biology phd from University of Oregon with a specialization in biochemistry, physiology, and endocrinology. Many of his ideas are not the mainstream but everything he writes about is extensively researched and cited. He has a number of articles on sugar but a good one to start with is Sugar Issues[0]. It can get a bit technical so I would recommend keeping wikipedia and google handy. It looks to have around 50-100 references for further investigation. Here's also one of his many radio interviews where he discuses sugar (starts in earnest with respect to sugar at around 14:35, but whole talk is great)[1]. Basically, sugars (glucose, fructose, sucrose, lactose) are healthy and protective for a wide variety of reasons - as long as they are able to be fully oxidized by the mitochondria, to produce carbon dioxide and a greater number of ATP. Many of the alleged "evils" of sugar are actually due to the polyunsaturated fats, which inhibit proper metabolism of sugar and damage cells in a variety of ways. One well established mechanism is by competing with glucose for oxidation, resulting in higher blood sugar levels. This is known as the Randall cycle (or glucose fatty acid cycle) and actually serves as the foundation for an as-of-yet unchallenged theory of type 2 diabetes. I highly recommend reading ray peat, and listening to his interviews. His intelligence, recall, and ability to synthesize information to form coherent biological models across a variety of topics are all-together astounding. I honestly recommend all of his articles and interviews. It takes some time and re-readings to fully grasp the concepts he advances, but it is well worth it. [0] http://raypeat.com/articles/articles/sugar-issues.shtml http://raypeat.com/articles/articles/sugar-issues.shtml [1] https://www.youtube.com/watch?v=Lx96YYKvA9w https://www.youtube.com/watch?v=Lx96YYKvA9w
  - tr1ck5t3r 9y ago
    http://www.youtube.com/watch?v=fL5-9ZxamXc&t=16m52s http://www.youtube.com/watch?v=fL5-9ZxamXc&t=16m52s Insulin = obesity 25g of carbs or less. Fasting with just water - After 3-4 days of putting up with Ghrelin the hunger hormone which also increases spatial intelligence arguably a survival mechanism in its own right, the body goes into Ketosis which is fat burning. At the same time the body will start repairing itself as seen in one extreme study carried out in 1971 at the University of Dundee on a 27yr old obese male who fasted on just water with periodic intakes of vitamins & minerals for 382days. Its what Christian Lent is about, its what the ancient Greeks call the "physician within", Ramamdan fasting which includes no fluids during daylight hours has the effect of causing a spike in blood sugar levels but is not quite as beneficial as plain old water fasting. Water fasting before chemo also increases the survival rates of some cancer patients, if you read the studies or even the summaries of the studies. Highest peak seen in Human Growth Hormone was 1250% which is more than you see in puberty, it also increases your metabolism so you lose weight properly, and under extreme conditions grey hair will turn back to its original colour, moles and skin inperfections shrivel up and dissappea. The liver is the only organ that is rejuvenated from the food you consume. Fasting basically rejuvenates the body, so much so it was reported in one encyclopedia printed in 1836, that Arabs used to live to be over 200 years old, not bad if you have a nice pension plan in place to retire soon!
rscho 9y ago
Fructose has the particularity among sugars that its uptake in the gut is not regulated, and can be easily metabolized. This means you can load your body with fructose, with both the benefits and nefarious consequences that implies.
js2 9y ago
With respect to endurance sports where you will exercise long enough to exhaust glycogen stores, you actually want a mix of fructose and another sugar such as maltodextrin. http://fellrnr.com/wiki/Fructose http://fellrnr.com/wiki/Fructose http://fellrnr.com/wiki/Nutrient_Timing http://fellrnr.com/wiki/Nutrient_Timing When you hear a marathon runner refer to hitting the wall, what's happenened is that they've exhausted their glycogen stores.
- noir_lord 9y ago
  Cyclists call it 'the bonk' and it's fucking horrible. It's like been incredibly drunk and tired at the same time. Happened to me the first time I did a 60 mile ride in winter, wind back was brutal, I got about 10 miles from home on the outskirts of town, found a petrol station ate a cornish pasty and two mars bars and it took about 30 minutes before I could summon the energy to get on the bike and coast home. I learnt the lesson the hard way that day. I've found it relatively easy to avoid since mostly by drinking at least a litre of isotonic an hour on the bike (adjusting for climate) and eating reasonable amounts of carbs the day before.
  - logfromblammo 9y ago
    Some people eat restricted carbohydrates and then exercise to bonk on purpose. It's based on research by a Dr. B.K. Pedersen of Copenhagen. And some medieval monks wore shirts made from hair. "Bonk training" seems like a perfectly horrible way to lose body fat.
- deleted 9y ago
  [deleted]
scottLobster 9y ago
I've found this guy's videos to be a good distillation of the issue. It's basically Lustig's work but there's some other sources as well. Why Sugar is as Bad as Alcohol: https://www.youtube.com/watch?v=f_4Q9Iv7_Ao https://www.youtube.com/watch?v=f_4Q9Iv7_Ao Food Industry's Secret Weapon (WHY Sugar is addictive & in 80% of Food): https://www.youtube.com/watch?v=LPxIssabhTc https://www.youtube.com/watch?v=LPxIssabhTc

ibejoeb 9y ago

Robert Lustig does a good talk about sugar metabolism in "Sugar: The Bitter Truth": https://www.youtube.com/watch?v=dBnniua6-oM https://www.youtube.com/watch?v=dBnniua6-oM Also, "The Trouble with Fructose": https://www.youtube.com/watch?v=Yh4JBXaKnmA https://www.youtube.com/watch?v=Yh4JBXaKnmA Despite the baity titles, it's a good talk with real biochemistry. Edit: better video added up top

agumonkey 9y ago
Lustig is not a joke, but I'd love to have other wise point of view on the matter.
- deegles 9y ago
  What would this other point of view show? I don't see how there can be alternative opinions on this, metabolism isn't that different between humans. I guess you could argue that he didn't reach the correct conclusion, but that's different point.
  - wutbrodo 9y ago
    Googling 'Lustig criticism' gives you a good place to start. Though with nutritional science, everything is so far from consensus (and when there is a consensus, it's 20 years behind the science) that you should treat this as a jumping-off point to read the literature instead of an authoritative rebuttal. http://www.alanaragonblog.com/2010/01/29/the-bitter-truth-about-fructose-alarmism/ http://www.alanaragonblog.com/2010/01/29/the-bitter-truth-ab... There's a section about halfway down where he discusses Lustig's claims that things like HFCS are metabolized differently and negatively.
  - agumonkey 9y ago
    Because I'm not a doctor or a biologist, so I need a few counterpoints as checks in order not to be blinded. It's just a quick check valve while I read more about the subject.
- ibejoeb 9y ago
  Me too. I know this is essentially his gig now, but I haven't seen anyone attack the science. If there's a reasonable refutation out there, I'm all ears.
  - jeffdavis 9y ago
    In his video he talks about the amount of salt in Coca Cola like it's part of some grand conspiracy. Coke has very little salt, so it makes me question a lot of his other claims.
    - crottypeter 9y ago
      I'm gonna echo GP >I haven't seen anyone attack the science. If there's a reasonable refutation out there, I'm all ears.
  - imcoconut 9y ago
    Ray Peat addresses the science better than anyone I've read. He's a biology phd from University of Oregon with a specialization in biochemistry, physiology, and endocrinology. Many of his ideas are not the mainstream but everything he writes about is extensively researched and cited. He has a number of articles on sugar but a good one to start with is Sugar Issues[0]. It can get a bit technical so I would recommend keeping wikipedia and google handy. It looks to have around 50-100 references for further investigation. Here's also one of his many radio interviews where he discuses sugar (starts in earnest with respect to sugar at around 14:35, but whole talk is great)[1]. Basically, sugars (glucose, fructose, sucrose, lactose) are healthy and protective for a wide variety of reasons - as long as they are able to be fully oxidized by the mitochondria, to produce carbon dioxide and a greater number of ATP. Many of the alleged "evils" of sugar are actually due to the polyunsaturated fats, which inhibit proper metabolism of sugar and damage cells in a variety of ways. One well established mechanism is by competing with glucose for oxidation, resulting in higher blood sugar levels. This is known as the Randall cycle (or glucose fatty acid cycle) and actually serves as the foundation for an as-of-yet unchallenged theory of type 2 diabetes. I highly recommend reading ray peat, and listening to his interviews. His intelligence, recall, and ability to synthesize information to form coherent biological models across a variety of topics are all-together astounding. I honestly recommend all of his articles and interviews. It takes some time and re-readings to fully grasp the concepts he advances, but it is well worth it. [0] http://raypeat.com/articles/articles/sugar-issues.shtml http://raypeat.com/articles/articles/sugar-issues.shtml [1] https://www.youtube.com/watch?v=Lx96YYKvA9w https://www.youtube.com/watch?v=Lx96YYKvA9w
- tr1ck5t3r 9y ago
  http://www.youtube.com/watch?v=fL5-9ZxamXc&t=16m52s http://www.youtube.com/watch?v=fL5-9ZxamXc&t=16m52s Insulin = obesity 25g of carbs or less. Fasting with just water - After 3-4 days of putting up with Ghrelin the hunger hormone which also increases spatial intelligence arguably a survival mechanism in its own right, the body goes into Ketosis which is fat burning. At the same time the body will start repairing itself as seen in one extreme study carried out in 1971 at the University of Dundee on a 27yr old obese male who fasted on just water with periodic intakes of vitamins & minerals for 382days. Its what Christian Lent is about, its what the ancient Greeks call the "physician within", Ramamdan fasting which includes no fluids during daylight hours has the effect of causing a spike in blood sugar levels but is not quite as beneficial as plain old water fasting. Water fasting before chemo also increases the survival rates of some cancer patients, if you read the studies or even the summaries of the studies. Highest peak seen in Human Growth Hormone was 1250% which is more than you see in puberty, it also increases your metabolism so you lose weight properly, and under extreme conditions grey hair will turn back to its original colour, moles and skin inperfections shrivel up and dissappea. The liver is the only organ that is rejuvenated from the food you consume. Fasting basically rejuvenates the body, so much so it was reported in one encyclopedia printed in 1836, that Arabs used to live to be over 200 years old, not bad if you have a nice pension plan in place to retire soon!

rscho 9y ago

Fructose has the particularity among sugars that its uptake in the gut is not regulated, and can be easily metabolized. This means you can load your body with fructose, with both the benefits and nefarious consequences that implies.

js2 9y ago

With respect to endurance sports where you will exercise long enough to exhaust glycogen stores, you actually want a mix of fructose and another sugar such as maltodextrin. http://fellrnr.com/wiki/Fructose http://fellrnr.com/wiki/Fructose http://fellrnr.com/wiki/Nutrient_Timing http://fellrnr.com/wiki/Nutrient_Timing When you hear a marathon runner refer to hitting the wall, what's happenened is that they've exhausted their glycogen stores.

noir_lord 9y ago
Cyclists call it 'the bonk' and it's fucking horrible. It's like been incredibly drunk and tired at the same time. Happened to me the first time I did a 60 mile ride in winter, wind back was brutal, I got about 10 miles from home on the outskirts of town, found a petrol station ate a cornish pasty and two mars bars and it took about 30 minutes before I could summon the energy to get on the bike and coast home. I learnt the lesson the hard way that day. I've found it relatively easy to avoid since mostly by drinking at least a litre of isotonic an hour on the bike (adjusting for climate) and eating reasonable amounts of carbs the day before.
- logfromblammo 9y ago
  Some people eat restricted carbohydrates and then exercise to bonk on purpose. It's based on research by a Dr. B.K. Pedersen of Copenhagen. And some medieval monks wore shirts made from hair. "Bonk training" seems like a perfectly horrible way to lose body fat.
deleted 9y ago
[deleted]

scottLobster 9y ago

I've found this guy's videos to be a good distillation of the issue. It's basically Lustig's work but there's some other sources as well. Why Sugar is as Bad as Alcohol: https://www.youtube.com/watch?v=f_4Q9Iv7_Ao https://www.youtube.com/watch?v=f_4Q9Iv7_Ao Food Industry's Secret Weapon (WHY Sugar is addictive & in 80% of Food): https://www.youtube.com/watch?v=LPxIssabhTc https://www.youtube.com/watch?v=LPxIssabhTc