carb questions... page

[haddock107]

Hey all! I'm a newbie here. My husband and I have changed to the paleo/ primal lifestyle (Crossfit & all!) a little over 2 months ago. We are sold. He's lost 30lbs. I'm smaller & more fit than I ever was playing soccer & running my whole life. We love it. However, our friends not so much.

I have a friend whose degree was in exercise science. Her and I got into a discussion yesterday when she found out about the "diet" we're on. She said, "Well, I just couldn't do that. I need carbs because I work out (blah blah blah)." I said, "Oh we work out hard." (I didn't want to get all snobby and tell her that our Crossfit 'warm-up' is probably equivalent to her gym 'workout' ) She replied, "Well you're only going to be able to uphold that diet for so long before your body totally crashes on you. You need carbs."
I just shrugged it off. I mean, I know there are hard-core athletes who eat this way no problem. But the "science" behind it I'm still unsure of, so I couldn't respond...
What do you say to all that?

[smilingjustalittlebit]

The fact that she has a degree does not make her an expert. She should actually do some reading of her own before blindly shooting it down.

The true science i'm unfamiliar with but what I do know, and all i need to know is this:

I no longer require sugar for energy. I no longer require all those healthy (cough) complex carbs for energy. Fat is my fuel and I will seek it everywhere I can find it!

[magnolia1973]

Paleo/Primal is not low carb.... Plenty of people here eat a ton of carbs and still comply with the suggested foods.

Atkins is low carb, you can elect to eat primal or paleo and be low carb. You can also elect to eat primal and paleo and be fairly high carb. She should see what Choco Taco eats!

She obviously is unaware of what is encouraged/allowed.

[Apex Predator]

Paleo is not low carb, it's low toxin. There are plenty of low-toxin carbs. Some specific medical conditions require minimal carbs, either for a time or permanently, just like some require all other manner of other modifications. Hell, there are people that essentially can't eat vegetables...

Most, though not all, serious athletes eventually require carbs for optimal performance. There is also profound differences between the first 6 months of low carb, the first year, the first 18 months, etc. Plenty of us didn't need carbs until a certain point.

[Neckhammer]

Carbs are not necessary beyond obligate glucose requirements which you can provide or your body can make via gluconeogenesis. Fat is a fine fuel source. Some people who bang away at the glycolytic pathway continuously may run into issues in the long run. Actually since your question is specific to finding info on why your choice to follow this type of eating plan let me suggest you look up Dr. Volek and Phinney. Or peruse this fellas website which does show specific athletic adaptations to a very low carb diet Peter Attia | The War on Insulin | Peter Attia, M.D., explains why everything you think you know about nutrition is wrong. Eating fat does not make you fat. This should at least give you a couple of starting points. I can't really expend the time or space needed to cover this topic in detail right here. Another interesting piece was written by Peter of hyperlipid here....Hyperlipid: Should we abandon the carbohydrate hypothesis of obesity? actually anything by him is golden.

There is nothing to fear from cutting carbs. Much of the banter is really what I consider to be a sort of low carb backlash. There is really still a lot that we don't know, but I would say if you feel good eating the way you are and your workouts are going well then keep up the great work!

[pklopp]

I have a friend whose degree was in exercise science. Her and I got into a discussion yesterday when she found out about the "diet" we're on. She said, "Well, I just couldn't do that. I need carbs because I work out (blah blah blah)." I said, "Oh we work out hard." (I didn't want to get all snobby and tell her that our Crossfit 'warm-up' is probably equivalent to her gym 'workout' ) She replied, "Well you're only going to be able to uphold that diet for so long before your body totally crashes on you. You need carbs."
I just shrugged it off. I mean, I know there are hard-core athletes who eat this way no problem. But the "science" behind it I'm still unsure of, so I couldn't respond...
What do you say to all that?

First, the empirical answer is this: anyone that is capable of surviving a Crossfit metcon workout, irrespective of diet, is doing quite well. The proof of that pudding is in the hypoglycemia that fails to materialize. Were carbohydrates essential for athletic performance, you would immediately know it as you would hit the wall hard ( pass out, actually ). Anyone who has experienced hypoglycemia can tell you that it is very difficult to mistake it for anything else.

For the scientific explanation: if you are not eating a lot of carbohydrates, then you are necessarily either eating a high fat ketogenic diet, or if you are not in ketosis, then you are eating a high protein diet.

Ketones are a more efficient fuel than glucose actually, requiring less oxygen to provide the same energy yield as an equivalent amount of glucose. Your heart will preferentially use ketones over glucose precisely for this reason. In addition, this is why the heart is surrounded by fat, both to provide cushioning against shocks, and a ready source of fuel. Moreover, when you are oxidizing fat for energy, you are breaking down triglyceride molecules into free fatty acids and a glycerol backbone. Luckily for you, that gives you a whole raft of circulating glycerol that can then be converted by the liver into glucose via hepatic gluconeogenesis. Further, anyone who has exercised strenuously knows the burn of lactic acid. Well, it turns out that lactic acid is another substrate for gluconeogenesis. So, you say that you are not in a state of nutritional ketosis? No matter, if your diet is high in protein, then you can feed that into the gluconeogenetic cycle.

I agree with your friend that glucose is an important substrate for energy metabolism, so important, in fact, that the body does not leave it up to the vagaries of diet for its supply. Rather, we all embody exquisite biochemical machinery to regulate glucose availability with all manner of inputs.

-PK

[fiercehunter]

You need to bone up for round 2. Read Dr. Jack Kruse website & ponder what he says about eating carbs out of season & stem cells & aging. Think about being "old on the inside". Then get even jiggier with it & read T.S. Wiley Lights Out. Listen to her talks on blogtalk radio with Sean Croxton. Carbs n workout, whoa, that is for dummies. Diana Shwarzbein, an endocrinologist says something similar. Your friend will not be able to accept concept of "old on the inside" BTW because most ppl think a lot of exercise is anti aging. Explain to her that she doesn't have complete info.

[lssanjose]

First, the empirical answer is this: anyone that is capable of surviving a Crossfit metcon workout, irrespective of diet, is doing quite well. The proof of that pudding is in the hypoglycemia that fails to materialize. Were carbohydrates essential for athletic performance, you would immediately know it as you would hit the wall hard ( pass out, actually ). Anyone who has experienced hypoglycemia can tell you that it is very difficult to mistake it for anything else.

For the scientific explanation: if you are not eating a lot of carbohydrates, then you are necessarily either eating a high fat ketogenic diet, or if you are not in ketosis, then you are eating a high protein diet.

Ketones are a more efficient fuel than glucose actually, requiring less oxygen to provide the same energy yield as an equivalent amount of glucose. Your heart will preferentially use ketones over glucose precisely for this reason. In addition, this is why the heart is surrounded by fat, both to provide cushioning against shocks, and a ready source of fuel. Moreover, when you are oxidizing fat for energy, you are breaking down triglyceride molecules into free fatty acids and a glycerol backbone. Luckily for you, that gives you a whole raft of circulating glycerol that can then be converted by the liver into glucose via hepatic gluconeogenesis. Further, anyone who has exercised strenuously knows the burn of lactic acid. Well, it turns out that lactic acid is another substrate for gluconeogenesis. So, you say that you are not in a state of nutritional ketosis? No matter, if your diet is high in protein, then you can feed that into the gluconeogenetic cycle.

I agree with your friend that glucose is an important substrate for energy metabolism, so important, in fact, that the body does not leave it up to the vagaries of diet for its supply. Rather, we all embody exquisite biochemical machinery to regulate glucose availability with all manner of inputs.

-PK

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