Low Carb is back?

Triathlon Forum
1

I spent a good number of hours reading some weblogs/researching a little bit on pubmed and reading some articles. If what I read is true, there seems to be quite a lot of new evidence in favor of carb restriction. This definitely shatters my own carb lover’s view of what comprises a balanced diet and seems to be quite contrary to the conventional wisdom as well.
So what is the deal ?

For those who are interested to read, these are some of the weblogs that I visited:
http://www.drbriffa.com/...hydrate-restriction/

http://www.marksdailyapple.com/category/carbs/

And some more scientific links with summaries:

http://www.ajcn.org/...ontent/full/86/2/276
From the abstract :“Recent studies show that, under conditions of carbohydrate restriction, fuel sources shift from glucose and fatty acids to fatty acids and ketones, and that ad libitum–fed carbohydrate-restricted diets lead to appetite reduction, weight loss, and improvement in surrogate markers of cardiovascular disease.”

Summary: " Recent studies have outlined LCD metabolism and shown that LCDs improve glycemic control and insulin resistance in healthy persons and in persons with type 2 diabetes. The instruction to limit carbohydrate intake, without specific reference to calorie intake, leads to a spontaneous reduction in calorie intake. In controlled trials for weight loss, the LCD leads to weight loss and improvements in fasting triacylglycerols, HDL cholesterol, and the ratio of total to HDL cholesterol over a 6–12-mo period. Clinical trials assessing the long-term safety and effectiveness of LCDs are needed. In the interim, the use of the LCD with careful monitoring of CVD risk factors and other variables associated with health appears reasonable.
The clinical use of and clinical research on LCDs have raised fundamental questions about insulin resistance and the regulation of cellular fuel utilization, as well as questions about whether dietary carbohydrate is an essential nutrient, and whether dietary fat causes heart disease. Because of their glucose- and insulin-lowering effects, LCDs should be evaluated as possible treatments for conditions related to hyperglycemia, hyperinsulinemia, and insulin resistance. We emphasize that strategies based on carbohydrate restriction have continued to fulfill their promise in relation to weight loss and that, contrary to early concerns, they have a g****enerally beneficial effect on most markers of CVD, even in the absence of weight loss. In combination with the intuitive and established efficacy in relation to glycemic control in diabetics, some form of LCD may be the preferred choice for weight reduction as well as for general health."

http://www.ajcn.org/...ontent/full/86/2/276
“Recent studies show that, under conditions of carbohydrate restriction, fuel sources shift from glucose and fatty acids to fatty acids and ketones, and that ad libitum–fed carbohydrate-restricted diets lead to appetite reduction, weight loss, and improvement in surrogate markers of cardiovascular disease.”

http://www.ncbi.nlm.nih.gov/...anel.Pubmed_RVDocSum
“These data suggest that diets lower in carbohydrate and higher in fat and protein do not increase the risk of type 2 diabetes in women. In fact, diets rich in vegetable sources of fat and protein may modestly reduce the risk of diabetes.”

http://www.ncbi.nlm.nih.gov/...anel.Pubmed_RVDocSum
“Dietary cholesterol from eggs increases plasma HDL cholesterol in overweight men consuming a carbohydrate-restricted diet.” This sounds a lot like atkins!

http://www.ncbi.nlm.nih.gov/...anel.Pubmed_RVDocSum
“Long-term effects of a high-protein weight-loss diet.”

http://www.ncbi.nlm.nih.gov/...anel.Pubmed_RVDocSum
“In summary, a very low carbohydrate diet resulted in profound alterations in fatty acid composition and reduced inflammation compared to a low fat diet”

2

The pre-packaged fad is probably back… but “low carb” for lean mass is proven. The problem with the fad is a dummy approach to ignoring the glycemic and insulin index and labeling all carbs as bad. There are bad times, but no bad carbs.

Performance-wise, track this and eat the right kind of carb at the right time. For optimization, it’s good to know what will help fuel/recover us the best.

And, of course, a glycogen burning swimming/biking/running machine needs more carbs. But that reason doesn’t give a free pass to pile on any and all carbs. There is a limit to how much freedom an athlete gets in carb intake before they start packing on the pounds.

“In combination with the intuitive and established efficacy in relation to glycemic control in diabetics, some form of LCD may be the preferred choice for weight reduction as well as for general health.”

Right on with Omega-3’s… awesome for increased insulin sensitivity.

3

Some of the papers include some important health implications which I think go beyond just gaining more lean mass (which of course by itself is an important health factor). The inflammatory markers were shown to decrease by consuming a carbohydrate restricted diet. The so called markers, have been also recently shown to be an important factor in CVDs. Some of the criticisms of old atkins diets (lack of vitamins, fiber etc.) also do not apply to the new recommendations as they incorporate a huge amount of veggies daily. The current dietary guideline published by the government of Canada recommends that 60% of the calories come from carbs (complex of course) which is quite contrary to what is suggested here.

4

Low carbs for diabetics is nothing new. This has been the norm for decades. Low carb diets are not for athletes though. May be OK for sedentary couch potatoes, but athletes need the carbs for optimal adaptation and performance.

Mike

5

Here is my opinion on the whole LCD issue:

These studies are all based upon the premise that we are eating the SAD (Standard American Diet) and sitting on our asses all day long in front of Oprah like 99% of America. As endurance athletes we have nutritional needs that go above and beyond what normal people have because of the depletion of fuel reserves we create almost daily. If we were sitting round eating donuts and Hungry Man TV dinners this might apply more to us as a population. To say as an endurance athlete you should go on a low carb diet is rediculous.

Dave

6

These studies are all based upon the premise that we are eating the SAD (Standard American Diet)
They are not, a few of the new ones considered LCD vs. Healthy diet for what it is defined conventionally.

7

Low carbs for diabetics is nothing new.
Well it must have been shockingly new for the experts, sitting in the American Diabetic Association, because it made them change their long lasting stance of not recommending low carb diets to diabetic patients.

http://www.nlm.nih.gov/...fullstory_59466.html

8

OK so maybe they were not comparing the cream puff diet to LCD, but did they consider people burning 2000 calories during exercise in a day? I think not. Perhaps it’s the KIND of carbs? I lowered all my markers by switching to gluten free sources of my carbs like teff, rice and tapioca while still eating them often in large amounts. Adkins style eating is just nuts, digesting muscle tissue through Ketosis is not a healthy way to lose weight or improve cholesterol numbers. Thanks for the links, perhaps it may help someone reduce their cholesterol by eating just a little better, possibly less refined foods. I’m just not sold that it’s making a comeback.

9

Atkins is definitely not the optimal diet for anyone, but a diet composed of 10-20% carbs coming from veggies and fruits (that’s a lot of veggies btw), 50% fat (coming from good fat sources), 30% protein is the subject of the question here.

I am not contemplating about the merits of strict carbohydrate restriction for endurance athletes but more for general health, but I also do think that it might influence the amount of CHO that athletes consume daily.

So I have some questions for you and everyone else about the proper refueling strategy for an athlete who burns 2000 kcal during daily training and another 2000 from RMR+normal activities. If the athlete follows a conventional diet of an endurance athlete, s/he consumes about 3000kcal from CHO, but the question is if s/he burned this much calories in the form of CHO to begin with ? Depending on the intensity of his training, s/he probably has burnt about 1500kcal in the form of CHO, so why should the athlete replace the burnt fat with carbohydrate ? I also can’t come up with a valid reason as why, except immediate post workout refueling for its proven recovery benefits, CHO should be the primary source of energy for athletes. Why shouldn’t we eat primarily fat and let the body replenish its CHO depleted stores from its available fat sources (bloodstream and adipose). I thought I knew why, but I am not sure about my conventional wisdom after reading the new stuff anymore.

In another note, Calorie restriction is also shown to be an effective way for battling aging, excessive oxidation is not that good for us after all. I can’t help but remember a female pro triathlete who looked 10 years older than her TWIN sister in a side by side photo. Are we doing a disservice to our bodies by burning 2000 calories a day ?

10

http://www.ajcn.org/...ontent/full/86/2/276
From the abstract :"Recent studies show that, under conditions of carbohydrate restriction, fuel sources shift from glucose and fatty acids to fatty acids and ketones, and that ad libitum–fed carbohydrate-restricted diets lead to appetite reduction, weight loss, and improvement in surrogate markers of cardiovascular disease."

If you reduce your carb intake, that means your calories come from protein and fat, you either eat 2-400g of protein and get osteoporosis as well as other problems, or you get your calories from fat and wouldn’t that increase cardiovascular disease?

11

2-400g of protein and get osteoporosis as well as other problems, or you get your calories from fat and wouldn’t that increase cardiovascular disease?

They are both myths. Recent studies, do not even blame cholestrole and saturated fat as much for CVDs, and there is no doubt about the value of good fat in cardio vascular health.

For osteoporosis and its relation to protein, check this : http://www.westonaprice.org/mythstruths/mtbones.html

12

The idea of gulping down a shot of olive oil after practice has me doubling over at the mere thought of it. If I do my workouts properly hard, it takes the entire golden hour of replenishment in order for my stomach/digestive to settle back down enough to handly anything other than simple carbs.

As for day to day eating, maybe I’m a freak or something, but too much protein leaves me feeling like crap the rest of the day.

13

I’m glad this made its way back to the top because I wanted to comment on it. good thread- thanks for posting this and the links. Valuable.

I think there is the issue of perspective when we talk about so-called “low carb”. My take is that most people’s eating habits involve a disproportionately high amount of carbohydrate, mostly refined and a lot of simple sugars. Perhaps when we talk about “low carb” we’re really talking about recalibrating to a more acceptable or more moderate percentage of carbohydrate in our diet. I’m not talking about the sort of fadish, low-carb “Hollywood” or “Miami” diets for weight loss here.

If a person who eats a lot of bread, refined foods (mostly carbohydrate, mostly simple) re-calibrated their same caloric intake with a different proportion of good fats, proteins, good carbohydrate sources, enough dietary fiber and good hydration I wager they would appreciate all the effects noted in your excellent links such as weight loss, reduction of inflamation, etc.

It’s not so much about a “low carb” diet for most people, it is about re-calibrating a disproportionately high carb, high calorie diet I think. For most Americans a balanced diet is “low carb” compared to what their used to eating.

14

Low carbs for diabetics is nothing new.
Well it must have been shockingly new for the experts, sitting in the American Diabetic Association, because it made them change their long lasting stance of not recommending low carb diets to diabetic patients.

http://www.nlm.nih.gov/...fullstory_59466.html

I have not looked at ADA stuff for probably 12 years. Back 12 years ago when I was finishing up my PhD in exercise phys, recommending a low or lower carb diet for type II diabetics was the norm. Maybe they did a couple of flip flops since then? Who knows. I have been too busy playing naval officer to pay much attention to the ADAs current positions. In any case, this does not seem at all new or controversial to me.

Mike