Healthy Eating

hugo29

bbam wrote: »

People become overweight by eating more calories than they expend.

how much calories are burned at night i wonder;)

El_Dangeroso

ford2600 wrote: »

E
Some light reading on the bio chemistry, I've quoted a small section

http://www.boards.ie/vbulletin/showp...&postcount=307

There are two other things about fructose that make it different from glucose. One is that all the fructose you eat is cleared on its first pass through the liver. In other words, the liver scarfs up all the fructose and immediately converts it to fat, while glucose stays in the bloodstream for some period of time. That’s why we call starches hyperglycemic molecules; they keep glucose levels in your bloodstream high for a long time. That is good for the brain - the brain loves to eat glucose. It’s good for the muscle. But fructose doesn’t actually supply any energy to your brain at all, it doesn’t supply any energy to your muscle; it only gets stored as fat. That’s really quite remarkable, if you think about it. You eat sucrose - one molecule of glucose and one molecule of fructose - that glucose is being used by your muscle and your brain - your brain loves getting that glucose - but the fructose is all just getting stored as fat.

That link is broken. When you talk about fructose 'being stored as fat' you are referring to de novo lipogenesis (creating new fat in fancy latin language), this is a VERY energy intense process. Less than 10% of the calories ingested as fructose make it through the end of the biochemical cascade to become a fatty acid. Hardly fattening now is it?

We have studies showing sugar found in fruit and honey DOES not have the same effect on the body as refined sugar (at least in rats), there's a reason the fruit is packaged up with vitamins, minerals and fibre, these are the very things that aid the proper digestion of sugar.

Arguing against fruit based on a really shoddy interpretation of biochemistry is misguided.

ford2600

Arguing against fruit based on a really shoddy interpretation of biochemistry is misguided.[/QUOTE]

Are you looking for an argument or what? I said I wasn't against fruit.

Here is full extract. If you bother to read it you'll see he differentiates between fructose in processed foods and fruit.



Interview
Lewis Cantley graduated from West Virginia Wesleyan College in chemistry and took his PhD in biophysical chemistry at Cornell University where he worked on enzyme kinetics. He did his postdoctoral studies at Harvard University where he stayed as an assistant professor until he moved to Tufts University where he discovered phosphoinositide-3-kinase, the enzyme critical to the control of growth that has dominated his research ever since. He returned to Harvard as a Professor of Cell Biology and later as a member of the new Department of Systems Biology and is now Director of the new Cancer Center at Weill Cornell Medical College and New York-Presbyterian Hospital.

thumbnail . Lewis Cantley
Quite early in your research career, you discovered the enzyme phosphoinositide kinase - usually known as PI3K - whose crucial activities are still central to your research. Can you briefly say what it does?
PI3K generates a lipid - and a lipid that wasn’t known prior to our discovery. It’s a very minor lipid - that’s why it had been missed - that is the product of inositol phosphorylation mediated by PI3K. Even at the time of our discovery that PI3K makes this novel lipid, we already had evidence that high levels of this enzyme correlated with malignant transformation of cells: in collaborations with Tom Roberts, Brian Schaffhausen and Ray Erickson we had shown that viruses that cause cancers in mice and chickens often do so by activating this novel enzymatic activity. So we knew early on that well-studied viral oncoproteins such as Src and polyoma middle T activate this lipid kinase. We went on to show that the product of PI3K, phosphatidylinositol-3,4,5-trisphosphate (PIP3), was quite high in cells transformed by these viruses. Because of its correlation with cancer, we suspected very early on that PIP3 was an oncolipid - although we didn’t actually name it that.

So the connection with cancer was established very early on and then, in an overview of PI3K signaling that you wrote in 2002 [1], you predicted that studies on the PI3K pathway would lead to new targets for diabetes and cancer. Did you realize then that metabolic disturbances like diabetes and cancer might actually be linked?
Well, we did because we published a paper in 1990 where we reported that not only was PI3K activated by growth factors like EGF and PDGF, but it was also activated by insulin [2]. In fact, insulin turned out to be the very best way to activate it. As we continued to pursue that finding through the very early 1990s, we and others found that virtually everything that insulin did required the activity of PI3K. In other words, inhibitors of PI3K or knockouts of PI3K in mice abrogated insulin signaling. Insulin-dependent glucose uptake, for example, required PI3K.

And as we were doing our work in mammalian systems - on cell lines and mouse knock-outs - other labs were studying worms and flies, and the gene encoding PI3K popped up in genetic mutants of flies, in a pathway that was downstream of the insulin/insulin-like growth factor (IGF) receptor. While mammals have separate but related receptors for insulin and IGF1, flies and worms have a single receptor that is the ancestor of these two receptors. So PI3K showed up genetically in the insulin/IGF-1 signaling pathway that controls cell growth in flies. In worms, it popped up in a nutrient-dependent age-related phenotype. In fact, it was called 'age-1' before it was identified as PI3K because loss-of-function mutations in the gene dramatically extend the lifespan of worms. The genetic network for ageing turned out to be the insulin receptor, IRS-1, PI3K, AKT, FoxO network - the same network that we were uncovering in mammalian systems.

So it was very clear by the late 1990s that PI3K evolved as a mediator of insulin/IGF-1 receptor signaling. And as full genome sequences of flies and worms became available it became clear that while the insulin receptor-PI3K-AKT-FoxO pathway was well conserved, other pathways for activating PI3K that we had found in mammalian cells were less conserved. And that led us to conclude that PI3K and PIP3 originally evolved to mediate insulin/IGF-1 signaling and to control nutrient uptake - particularly glucose uptake in response to feeding - and distribute it into the appropriate tissues for the organism to grow.

What you are mostly focused on now is specific disturbances of growth-related signaling networks in tumor cells that might suggest new drug targets, and I’d like to ask you about one noticeable thing about these studies - the frequent discovery of apparently paradoxical results. Would you like to say why these studies so often throw up paradoxes?
I think what we’re learning, of course, is that biological systems are far more complicated than we’d imagined. As we acquire tools that allow us to acutely knock out or knock down the expression of a particular gene, or have a drug that inhibits a particular step in a metabolic pathway or signaling pathway, we are finding that the system responds to these perturbations by attempting to reactivate the pathway. In other words, a lot of what we call robustness in nature comes about because biological systems have numerous negative feedback regulatory networks that sense when the system is out of balance and become altered to restore homeostasis. So some of the paradoxes come from the fact that whenever you inhibit a component of a signaling or metabolic network, you end up reactivating things upstream of it, giving a result that’s the opposite of what you expected to see.

In metabolic networks particularly, it’s been known for a long time that there are all kinds of feedback control. One example of a paradox from our research was the observation that pyruvate kinase, which is the enzyme in glycolysis that synthesizes ATP, actually tends to get turned down in cancer cells. This is paradoxical because cancer cells are typically utilizing glucose at 50- to 100-fold the rate of the normal tissue surrounding it, so why would they want to turn down one of the steps in that pathway and make less ATP? In the end, we figured out that it’s because that allows the cells to use the intermediates in glycolysis for other purposes than just making ATP, such as making NADPH, or making ribose, or making serine or glycine [3].

These are for biosynthetic pathways?
That’s right. The cancer cell of course needs to grow, and it needs to be able to control its oxidation-reduction potential. Those are typically a greater challenge for a cancer cell than just making ATP, which it can do through oxidative phosphorylation in mitochondria. So if you turn down ATP synthesis through glycolysis because you’re using glucose intermediates for metabolic processes, you can make up for that in the mitochondria and the cell is fine.

So would you conclude that you really need to know your way around metabolism before you can start to predict what will happen if you interfere with a particular step in the pathway?
That’s right. It’s only now that we have the tools to acutely perturb metabolic systems and monitor what happens, and we can really begin to understand the wiring diagrams of these pathways.

I’d like to ask you one last question, on fructose. You’ve written recently on the very topical issue of whether fructose is a particularly important cause of metabolic disease [4] and, as we now know, with possible very strong links to cancer. As I understand it, sucrose - and even other carbohydrates - in excess can be metabolized to fructose. So if we’re just eating too much carbohydrate generally, does it really matter whether it’s fructose or any other kind?
It turns out that it does matter. Quite honestly, four or five years ago I was in your camp of assuming, you know - fructose, glucose, they have exactly the same number of calories per gram, they can be interconverted instantly inside most cells, so what does it matter? The answer is, it’s really important - and quite striking - because the liver differentially metabolizes fructose and glucose. This specialization is pretty much unique to the liver; in any other cell, the fructose and glucose are pretty much interchanged quite rapidly. But liver does not have hexokinase, so it cannot phosphorylate fructose at the six position. This is in contrast to glucose, which can be phosphorylated at the six position in the liver by glucokinase to make glucose-6-phosphate, which is then converted to fructose-6-phosphate. And that is then phosphorylated at the one position by phosphofructokinase (PFK), which is - and here’s the key point - the ultimate gatekeeper for entering glycolysis. In contrast, fructose that enters the liver is phosphorylated at the one position by fructokinase (also called ketohexokinase) to make fructose-1-phosphate rather than fructose-6-phosphate. The liver is almost unique in regard to the ability to differentially metabolize glucose and fructose.

And that matters because…?
That matters because once it’s phosphorylated at the one position, fructose can be a substrate for aldolase, and shoot down the glycolytic pathway, bypassing the gatekeeper PFK, which is the control step for going into glycolysis. In most tissues, if the cell finds itself with plenty of ATP and plenty of citrate (the building blocks for making fatty acids), it will stop all flux through glycolysis because ATP and citrate inhibit PFK - a classic example of a metabolic negative feedback control. So the glucose that enters the cell can still get phosphorylated but it doesn’t go down glycolysis and doesn’t get converted to fat but rather gets stored as glycogen or exits the cell.

But in the liver, fructose bypasses that whole machinery, because it doesn’t need PFK; it gets phosphorylated at the one position directly, without phosphorylation of the six position first and, as a consequence, now becomes a substrate for aldolase, and it produces even higher levels of ATP and citrate that go on to make fatty acids. No matter how much you’ve eaten, you will still make more fat if you eat fructose.

There are two other things about fructose that make it different from glucose. One is that all the fructose you eat is cleared on its first pass through the liver. In other words, the liver scarfs up all the fructose and immediately converts it to fat, while glucose stays in the bloodstream for some period of time. That’s why we call starches hyperglycemic molecules; they keep glucose levels in your bloodstream high for a long time. That is good for the brain - the brain loves to eat glucose. It’s good for the muscle. But fructose doesn’t actually supply any energy to your brain at all, it doesn’t supply any energy to your muscle; it only gets stored as fat. That’s really quite remarkable, if you think about it. You eat sucrose - one molecule of glucose and one molecule of fructose - that glucose is being used by your muscle and your brain - your brain loves getting that glucose - but the fructose is all just getting stored as fat.

But does it also mean that you get hungrier - you want more sugar if you’re using fructose rather than glucose?
Exactly. You would have to eat exactly twice as much sucrose as starch to get the same amount of energy supplied to your muscle and brain. The brain realizes that, it keeps relaying a feedback so that the more sugar you eat, the more it wants you to eat. Hence the addiction to sweetness. That’s the dangerous thing about this molecule.

You might ask - well why did we evolve such a complicated system? Why does only the liver feed fructose straight into fat? I think it’s quite clear why this happens. We have a symbiotic relationship with plants. Plants want to spread their seeds around, so they surround them with fructose. High-fructose material surrounding the seeds gets us and other animals to eat them and this craving of fructose makes us eat them a lot and we end up carrying their seeds around and spreading them. But at the same time, it gives us an advantage because those fruits ripen just at the end of the growing season, which generally means, in almost all environments, that you’re not going to have much to eat over the next few months. So the best way to survive is to convert everything you eat at that time into fat. That is the long-term storage mechanism that allows you to survive until the next growing season. That’s why fructose was spectacular for us 10,000 years ago, getting us through these famines that we faced every year. But today we don’t have famines and so we just get fat.

Does this put a whole new gloss on Eve and that apple?
You’d probably have to eat about a bushel of apples to get the same amount of fructose as in a 40 oz Coke, which we’re trying to ban here in New York City unsuccessfully.

And here’s an additional comment. The way we’ve attempted to avoid this problem is by using artificial sweeteners. The problem with those is that a disconnect ultimately develops between the amount of sweetness the brain tastes and how much glucose ends up coming to the brain.

So the brain figures you have to eat more and more and more sweetness in order to get any calories out of it. The consequence of people eating lots of sweeteners, no matter what they are - whether they’re natural or unnatural - is that it increases the addiction for the sweetness. As a consequence, at the end of the day, your brain says, 'OK, at some point I need some glucose here'. And then you eat an entire cake, because nobody can hold out in the end. The only way really to prevent this problem - to break the addiction - is to go completely cold turkey and go off all sweeteners - artificial as well as fructose. Eventually the brain resets itself and you don’t crave it as much.

Genghis Cant

runawaybishop wrote: »

People get fat by eating too much.

Too much what? Celery? Cake?

Way too simplistic. If you take in 3000 Kcals and burn 5000 Kcals, you're in deficit.

runawaybishop

Genghis Cant wrote: »

Too much what? Celery? Cake?

Way too simplistic. If you take in 3000 Kcals and burn 5000 Kcals, you're in deficit.

If you take in 3k and burn 5k you are not eating too much.

Genghis Cant

runawaybishop wrote: »

If you take in 3k and burn 5k you are not eating too much.

Correct.

So " People get fat by eating too much" is incorrect.

El_Dangeroso

ford2600 wrote: »

Are you looking for an argument or what? I said I wasn't against fruit.

Here is full extract. If you bother to read it you'll see he differentiates between fructose in processed foods and fruit.

I'm not entirely sure what your point is? You quoted a section of the article, so I made a point about that section. If you're not against fruit that's fine. That's all my point was.

Insulin is not the cause of getting fat by the way. 'Spiking' insulin is not something a healthy person should fear.

Genghis Cant

As part of corporate day I attended lately, there was a nutritionist present who gave a talk on healthy eating. She said this 5 a day is outdated and the new 5 a day is 9 a day. I think many present would have struggled to name 9 items of fruit/veg never mind consuming them in a day!

ABlur

I like the qoute from Brian the dog in Family Guy when asked for his dietary tips: " put down the fork!"

runawaybishop

Genghis Cant wrote: »

Correct.

So " People get fat by eating too much" is incorrect.

No, it is not. :rolleyes:

Genghis Cant

runawaybishop wrote: »

No, it is not. :rolleyes:

:rolleyes::rolleyes:The world is flat. :rolleyes::rolleyes:

hugo29

Genghis Cant wrote: »

:rolleyes::rolleyes:The world is flat. :rolleyes::rolleyes:

My head keeps banging against the wall

hugo29

Genghis Cant wrote: »

Correct.

So " People get fat by eating too much" is incorrect.

Jayus at long last the voice of reason,

runawaybishop

Genghis Cant wrote: »

:rolleyes::rolleyes:The world is flat. :rolleyes::rolleyes:

Nice one.

Seriously though, what is wrong with saying that people get fat by eating too much? You said earlier on that this was too simplistic, but it is that simple.

biddy2013

hugo29 wrote: »

Jayus at long last the voice of reason,

have you a study to back that up now:D

A cow called Daisy

The fact that there seems to be different opinions from different nutritionists shows how complex the whole issue is. I believe that a healthy diet would consist

Plenty of fresh fruit and veg. (Frozen veg may be better as it is fresher than what may of been in a shop for a week.
Plenty of nuts,seeds and pulses
Natural food (porridge etc). Avoid processed food where possible
Reduce intake of biscuits and snacks, particularly fizzy drinks and high salt content snacks.
Drink water regularly throughout the day

I remember being told by dietitian that all those in her profession don't live to 100 either. Also, that eating fruit and veg that can be grown locally is better for us as it provides us with immunity to our 'native' illnesses. (Similar to biestings). Limits us a bit in Ireland as she said herself, but just repeating the point.

Obviously, some of these may not suit those (like myself) that have underlying medical conditions. However, the proverb of 'a little of what you fancy does you good' should also be followed.
That my tuppence worth anyway.

hugo29

biddy2013 wrote: »

have you a study to back that up now:D

Just finishing the calculations here now

biddy2013

A cow called Daisy wrote: »

Drink water regularly throughout the day

yes, 100% on that, i have a few half pint glasses filled with water around the house, also have a bottle of water in the milking parlour.

El_Dangeroso

A cow called Daisy wrote: »

I remember being told by dietitian that all those in her profession don't live to 100 either.

The biggest predictor of a long and healthy life isn't diet, it is not smoking and having good social support network around you with strong and loving relationships.

biddy2013

El_Dangeroso wrote: »

The biggest predictor of a long and healthy life isn't diet, it is not smoking and having good social support network around you with strong and loving relationships.

thats crap oh's parent where both dead young his mother died at 46 and his father died at 55. Both non drinkers and non smokers, when your time is up your time is up. His father played hurling for dublin and was as fit as a fiddle

Muckit

I find a lot of the apples and grapes that I buy very 'waxy'. Possibly sprayed with something to give them a shine or keep them fresh? Not good anyway

On the water thing. Again moderation. One could be Leeching vital vitamins and minerals as well as going to the loo all the time!

mayota

Processed foods are the problem. Look at the people years ago eating big feeds bacon and cabbage, chops, spuds with lashings of real butter. Pints of fresh milk. All from the farm. And they were all thin.

reilig

Muckit wrote: »

I find a lot of the apples and grapes that I buy very 'waxy'. Possibly sprayed with something to give them a shine or keep them fresh? Not good anyway

Look at killer diseases such as Diabetes and Cancer. Their prevalance has increased in multiples in recent years. This is due to what we take into our bodies. Years ago, when diabetes was less prevalent, there was very little processed food in this country. People lived on basics - meat, potatoes, fish, native vegetables. If you had a few fruit trees, you stored the fruit and ate it sparingly - you didn't eat it continuously until it was all gone. It was a treat that you had once or twice a week. Those people survived. If fruit couldn't be grown in this country, you didn't eat it. High sugar fruits like grapes, oranges or pineapple that we have nowadays are grown in hotter climates - sometimes you have to ask yourself if we are meant to be eating high sugar fruits that aren't grown in our climate in such quantities? In Ireland we grow lower sugar fruit like apples, berries, plums etc because the sun is not there for ripening and making a lot of sugar in them

How were our ancestors healthy? They ate a balanced diet which consisted mainly of vegetables and meat. Sugar, be it the natural type found in fruit or processed sugar, was taken in moderation. The wealthy who ate mainly rich foods, a lot of red meat, exotic fruit grown indoors, and took a lot of alcohol, got gout!

As for chemicals on fruit. I suspect that there is a major link between fruit and veg sprayed with chemicals and modern illnesses.

Genghis Cant

mayota wrote: »

Processed foods are the problem. Look at the people years ago eating big feeds bacon and cabbage, chops, spuds with lashings of real butter. Pints of fresh milk. All from the farm. And they were all thin.

They were working hard physical jobs though, high revs, burning plenty of fuel!

On the short term you can take in huge amounts of Kcals once youre burning it off (Eg Ian Thorpe 10000Kcals/day)
Longer term I think you're better off being half hungry if you want to live longer.

biddy2013

how many times do you hear people saying they are starving, they re not starving ,if you lived in fammine starved areas you might be starving

El_Dangeroso

biddy2013 wrote: »

thats crap oh's parent where both dead young his mother died at 46 and his father died at 55. Both non drinkers and non smokers, when your time is up your time is up. His father played hurling for dublin and was as fit as a fiddle

And some people smoke well into their 90's, one example means nothing, that's why you study big groups of people.

biddy2013

El_Dangeroso wrote: »

And some people smoke well into their 90's, one example means nothing, that's why you study big groups of people.

sure you could eat healthy and not drink and be run over by a bus tomorrow

El_Dangeroso

biddy2013 wrote: »

sure you could eat healthy and not drink and be run over by a bus tomorrow

True that, but I'm much more likely to die from a heart attack or stroke than a bus.

Sam Kade

biddy2013 wrote: »

how many times do you hear people saying they are starving, they re not starving ,if you lived in fammine starved areas you might be starving

It's just a saying which has been used here for generations, maybe it started during the famine.

mikefoxo

mayota wrote: »

Processed foods are the problem. Look at the people years ago eating big feeds bacon and cabbage, chops, spuds with lashings of real butter. Pints of fresh milk. All from the farm. And they were all thin.

My father has eaten a diet like that for all his life. Works outside everyday of his life, fit as a fiddle. He had a heart attack last September. Luckily he's okay now, but he always says it's the one thing he thought he'd never get. Just because you look healthy and don't eat a lot of processed food doesn't mean you're fighting fit