Fat Head: Tom Naughton's manifesto for low-carb eating

12. March 2010 William Davis (16)
I just got back from Jimmy Moore's low-carb cruise to the Bahamas.

Among the many interesting people I met on the cruise was the creator of the documentary film, Fat Head, Tom Naughton.

Tom brings both creative insights into low-carbohydrate eating as well as humor. Low-carb eating can be a pretty contentious issue, but Tom made it fun. He will make you laugh about many of the odd notions we have about diet.

Among the best parts of Fat Head is Tom's portrayal of the effects of carbohydrates on insulin and fat metabolism:






Fat Head joins the ranks of films like Food, Inc, that make nutrition information entertaining. For anyone interested in a unvarnished look at diet, weight loss, along with a few laughs along the way, Tom Naughton's Fat Head is worth viewing.

Oatmeal: Good or bad?

11. March 2010 William Davis (67)

You've heard it before: oatmeal reduces cholesterol. Oatmeal producers have obtained permission from the FDA to use a cholesterol-reducing claim. The American Heart Association provides a (paid) endorsement of Quaker Oats.

I've lost count of the times I've asked someone whether they ate a healthy breakfast and the answer was "Sure. I had oatmeal."

Is this true? Is oatmeal heart healthy because it reduces LDL cholesterol?

I don't think so. Try this: Have a serving of slow-cooked (e.g., steel-cut, Irish, etc.) oatmeal. Most people will consume oatmeal with skim or 1% milk and some dried or fresh fruit. Wait an hour, then check your blood sugar.

If you are not diabetic and have a fasting blood sugar in the "normal" range (<100 mg/dl), you will typically have a 1-hour blood glucose of 150-180 mg/dl--very high. If you have mildly increased fasting blood sugars between 100 and 126 mg/dl, postprandial (after-eating) blood sugars will easily exceed 180 mg/dl. If you have diabetes, hold onto your hat because, even if you take medications, blood sugar one hour after oatmeal will usually be between 200 and 300 mg/dl.

This is because oatmeal is converted rapidly to sugar, and a lot of it. Even if you were to repeat the experiment with no dried or fresh fruit, you will still witness high blood sugars in these ranges. Do like some people and pile on the raisins, dried cranberries, or brown sugar, and you will see blood sugars go even higher.

Blood sugars this high, experienced repetitively, will damage the delicate insulin-producing beta cells of your pancreas (glucose toxicity). It also glycates proteins of the eyes and vascular walls. The blood glucose effects of oatmeal really don't differ much from a large Snickers bar or bowl of jelly beans.

If you are like most people, you too will show high blood sugars after oatmeal. It's easy to find out . . . check your postprandial blood sugar.

In past, I recommended oat products, specifically oat bran, to reduce LDL, especially small LDL. I've changed my mind: I now no longer recommend any oat product due to its blood sugar-increasing effects.

Better choices: eggs, ground flaxseed as a hot cereal, cheese (the one dairy product that does not excessively trigger insulin), raw nuts, salads, leftovers from last evening's dinner.

Mustard: Super health food?

6. March 2010 William Davis (32)
Could mustard--yes, the yellow condiment you smear on hot dogs--be a super heart healthy food in disguise?

Consider that mustard contains:

Vinegar

Turmeric

No appreciable sugar


The vinegar slows gastric emptying, resulting in slower absorption of any carbohydrates and a reduced glucose area-under-the-curve. Of the little fats contained (about 3 grams per 1/4 cup), most are desirable monounsaturates. Mustards are relatively rich in selenium, with 20 mcg per 1/4 cup, helpful for protection against cancer and thyroid disease, and magnesium, 31 mg per 1/4 cup.

Turmeric is added to most mustards. One of the constituents of turmeric, curcumin, the substance that confers the bright yellow color, has been a focus of interest for its anti-inflammatory effects. Curcumin has been documented to reduce activity of the inflammatory enzymes cyclooxygenase-2 (COX-2), lipoxygenase, and reduce activity of inflammatory signal molecules, tumor necrosis factor-alpha (TNF-a), interleukin (IL)-1,2,6,8, and 12, and monocyte chemoattractant protein (MCP). Curcumin also has been shown to reduce LDL oxidation, a potentially important step in atherosclerotic plaque formation. Turmeric is used as a tea by Okinawans. (Hmmmm . . . )

Turmeric content of mustard can vary, of course. Likewise, sugar content. Look for mustards that are not sweetened, so avoid honey mustard in particular. Look for hot, brown, horseradish, Dijon, etc. If there is a downside to mustard, it's sodium content, though the 709 mg per 1/4 cup should only be a problem for those who are sodium-sensitive (African Americans, in particular).

So perhaps mustard isn't exactly a super health food. But it may have some bona fide health effects and should be used generously especially if you are concerned about blood sugar and inflammatory phenomena.

Exercise and blood sugar

5. March 2010 William Davis (30)
There is no doubt that exercise yields benefits across a spectrum of health: reduced blood pressure,  reduced inflammation, reduced blood coagulation, better weight control, stronger bones, less depression, reduced risk for heart attack.

Exercise also influences blood sugar. Diabetics understand this best: Exercise reduces blood sugar 20, 30, 50 or more milligrams. A starting blood sugar, for instance, of 160 mg/dl can be reduced to 80 mg/dl by jogging or riding a bicycle. (I recently had brunch at an Indian restaurant with my family. Blood sugar one-hour postprandial: 134 mg/dl. I was sleepy and foggy. I got on my stationary bike and pedalled at a moderate clip for 60 minutes. Blood sugar: 90 mg/dl.)

Could the reduction of blood sugar with exercise be THE reason that exercise and physical activity provide such substantial benefits?

Think about it. Reduced blood sugar:

1) Reduces risk for future cardiovascular events.
2) Reduces glycation of proteins, i.e., reduced glucose binding to proteins like the ones in artery walls and the lenses of your eyes.
3) Reduces blood coagulation
4) Reduces endothelial dysfunction (abnormal artery constriction that leads to atherosclerosis)

This might explain why it doesn't require high levels of aerobic activity to derive benefit from exercise, since even modest efforts (e.g., a 15-minute walk after eating) reduce blood sugar substantially.

The incredible 33-year, 18,000-participant Whitehall study tells us that a postprandial (after-eating) blood sugar of an impossibly-difficult 83 mg/dl is required to erase the excess cardiovascular risk of blood sugar. Could this simply be telling us that physical activity or exercise is required to suppress blood sugars to these low levels?

It makes me wonder if an index of the adequacy of exercise is your post-exercise blood glucose.

The most important weight loss tool

4. March 2010 William Davis (15)

Question: What is the most effective tool available to help you lose weight? 


A pedometer (walk 10,000 steps, etc.)?

A treadmill? 




A bicycle?






No. None of the above. 

The most important tool you can use to achieve weight loss is your glucose monitor:



Timing of blood sugars

3. March 2010 William Davis (5)
Because different foods generate different blood sugar (glucose) responses, the timing of your blood sugar is an important factor to consider.

This question has come up a number of times. Commenters have asked whether the one-hour postprandial glucose is timed with the start of the meal or the conclusion of the meal.

In my view, if we simply ignored all aspects of meal composition, then blood glucose should be obtained one hour after the conclusion of a meal. This is because most mixed meals (i.e., mixed in composition among proteins, fats, and carbohydrates) yield peak blood glucose levels at 60-90 minutes after consumption. Timing blood glucose to 60 minutes after the conclusion of a meal puts the sample right about at the peak.

But this is an oversimplification. For instance, here is the blood glucose behavior after so-called "complex" carbohydrates wheat bread, rye bread, rye made with beta glucan, and whole wheat pasta (50 grams carbohydrates each) in slender, healthy volunteers, mean age 29 years:


From Juntunen et al 2002

Note that blood glucose peaks at 35 minutes postprandial. (To convert glucose in mmol/L to mg/dl, multiple by 18. Thus, whole wheat bread increased blood glucose from 94 mg/dl to 122 mg/dl. Also note the lower peak glucose for pasta, but sustained higher glucose levels hours later.)

In another study, older (mean age 64 years), overweight (BMI 27.9) females with diabetes were given 50 grams carbohydrate, 50 grams carbohydrate with olive oil, or 50 grams carbohydrate with butter:


From Thomsen et al 2003. Control meal of soup plus 50 g carbohydrates ({blacktriangledown}), the control meal plus 80 g olive oil ({circ}), and the control meal plus 100 g butter (•).

In this experience, note that postprandial glucose peaks 60-120 minutes after the meals (consumed within 10 minutes), delayed more when either oil is included. Blood glucose started at 144 mg/dl and peaked as high as 230 mg/dl with carbohydrates only; peaks were reduced (along with AUC) when oil was included. (Note the differential effect, olive oil vs. butter.)

These two sets of observations give you a range of blood glucose behavior. One side lesson: Carbohydrates should never consumed by themselves, else you will pay with a high blood sugar (not to mention the hypoglycemic response later for many).

Psssst . . . There's sugar in there

1. March 2010 William Davis (13)
You non-diabetics who check your postprandial blood sugars already know: There are hidden sources of sugar in so many foods.

By now, everybody should know that foods like breakfast cereals, breads, bagels, pretzels, and crackers cause blood sugar to skyrocket after you eat them. But sometimes you eat something you thought was safe only to find you're showing blood sugars of 120, 130, 150+ mg/dl.

Where can you find such "stealth" sources of sugars that can screw up your postprandial blood sugars, small LDL, inflammation, blood pressure, and cause you to grow visceral fat? Here's a few:

Balsamic vinaigrette
Many commercially-prepared balsamic vinaigrettes, especially the "light" varieties, have 3 or more grams carbohydrates per tablespoon. Generous use of a sugar-added vinaigrette can therefore provide 12+ grams carbs. (Some, like Emeril's and Wish Bone, also contain high-fructose corn syrup.)

Hamburgers
I learned this lesson the hard way by taking my blood sugar after having a hamburger, turkey burger, or vegetarian burger (without bun): blood sugar would go way up. The effect is due to bread crumbs added to the meat or soy.

Tomato soup
If it were just tomatoes, it would still be somewhat high in sugars. But commercially-prepared tomato soup often contains added high-fructose corn syrup, sucrose, and wheat flour, bringing sugar totals to 12 to 20+ grams per half-cup. A typical 2-cup bowl of tomato soup can have upwards of 80 grams of sugar.

Granola
Sure, granola contains a lot of fiber. But most granolas come packed with sugars in various forms. One cup of Kellogg's Low-fat Granola with Raisins contains an incredible 72 grams (net) carbohydrates, of which 25 grams are sugar.


Given modern appetites and serving sizes, you can see that it is very easy to get carried away and, before you know it, get exposed to extraordinary amounts of sugar and carbohydrates eating foods you thought were healthy.

And don't be fooled by claims of "natural" sugar. Sugar is sugar--Just check your blood sugar and you'll see. So raw cane sugar, beet sugar, and brown sugar have the same impact as white table sugar. Honey, maple syrup, and agave? They're worse (due to fructose).

How low should blood sugar be?

28. February 2010 William Davis (0)
What should your blood sugar (glucose) be after eating?

Take a look at the data from the Whitehall study reported in 2006. The Whitehall Study stands apart from other studies in that it was very large (over 18,000 participants) who were observed for an unusually long time (33 years). All participants were administered a 50 gram glucose "challenge" at the start with glucose levels checked after the glucose challenge.

Here's what they found:




From Brunner et al 2006.
"Heart scans" are not always heart scans

"Heart scans" are not always heart scans

18. July 2007 William Davis (6)
Beware of the media reports now being issued that warn that "CT heart scans" pose a risk for cancer.

One report can be viewed at
http://www.webmd.com/cancer/news/20070717/ct-heart-scan-radiation-cancer-risk.

This was triggered by a Columbia University study of risk for cancer based on the dose of radiation used in CT coronary angiograms. Theoretically, exposure to the radiation dose of CT coronary angiography can raise risk for cancer by 1 in 143 women if radiated in their 20s just from that single exposure.

If you've been following the Track Your Plaque discussion, as well as my diatribes in the Heart Scan Blog, you know that the media got it all wrong. The "heart scans" they are referring to are not the same as the heart scans that we discuss for the Track Your Plaque program.

A conventional heart scan (of the sort we refer to) exposes the recipient to 4 chest x-rays of radiation if an EBT device is used, around 8-10 chest x-rays of radiation if a 64-slice CT scanner is used. For the quality of information we obtain from these screening heart scans, we feel that it's an acceptable exposure.

The "heart scan" this study and subsequent reports refer to is not truly a screening heart scan, but a CT coronary angiogram, or CTA. CTAs are performed on the same CT or EBT devices, but involve far more radiation. CTA exposes the recipient to about 100 chest x-rays of radiation on a 64-slice device (more or less, depending on the way it is performed.) Just a couple of years ago, some centers were performing CTA on 16-slice devices, a practice I and the Track Your Plaque program vocally opposed, since up to 400 chest-rays of radiation were required! I even called a number of centers advising them that they were putting the public in jeopardy. CTAs also require injection of x-ray dye, just like any conventional angiogram.

CTA on 64-slice CT scanners require the same radiation exposure as a conventional heart catheterization, an issue glossed over in most conversations. In other words, the test that many of my colleageus so casually recommend poses a similar risk.

The message: the test I advocate for screening for coronary heart disease is a CT or EBT heart scan, not a CT coronary angiogram. CTA is a useful test and will get better and better as the engineers discover ways to reduce radiation exposure. But, in 2007, CTA is a diagnostic device, not a screening device. If you require an abdominal CT scan because your doctor suspects pancreatic cancer, or a CT scan of the brain because you might have a life-threatening aneurysm causing double-vision or seizures, it would be silly to not undergo the scan because of long-term and theoretical cancer risk.

But undergoing a CT coronary angiogram for screening purposes is ridiculous with present technology. I've said it before and I will say it--shout it--again:

CT coronary angiograms are not screening procedures; they are diagnostic procedures that should be taken seriously and do indeed pose measurable risk for cancer, a risk that is presently unacceptable for a screening test.

You wouldn't undergo a mammogram to screen for breast cancer if it exposed you to 100 chest x-rays of radiation, would you? Screening tests should be safe, reliable, accurate, and inexpensive. CT coronary angiography is none of these things. Genuine heart scans--the kind the Track Your Plaque program talks about and relies on--is all of those things.
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Comments (6) -

  • Anonymous

    7/19/2007 12:16:00 AM |

    Dr. Davis, would you please specify the millisievert values you are assuming for chest x-ray, EBCT Ca score, MSCT Ca score, and CT angiogram? I just got a 64-slice Ca score and they told me I received an effective dose of 2 mSv. Would a CT angiography typically result in 20 mSv?

  • Dr. Davis

    7/19/2007 12:59:00 AM |

    Hi,

    Please see my Blog post, CT scans and radiation exposure at http://heartscanblog.blogspot.com/2007/06/ct-scans-and-radiation-exposure.html

    You may notice some differences. There's enormous variation in exposure, depending on how it's measured, how the scan is performed, type and manufacturer of scanner. However, you can get a good idea of ballpark figures from the table in the blog post.

  • Dr. Davis

    7/19/2007 1:02:00 AM |

    Let me try that URL again:

    http://heartscanblog.blogspot.com/
    search/label/CT%20scans%20and%
    20radiation%20exposure

    Or, go to the left sidebar of Blog contents and see "CT scans and radiation"

  • JT

    7/22/2007 1:55:00 AM |

    I watch Fox news.  And with that statement I'm sure some are rolling their eyes.  Never before in the history of America has declaring what news channel one watches apparently pigeonholed one on their political views.  

    Like many I get my news from different locations: internet blogs, TV, radio, magazines, newspapers, etc, but in the morning I often watch Fox and Friends.  I do so for two reasons I suppose, the first being that I enjoy the joking around / humor on the set.  The second reason why I watch Fox is because it goes out of its way to present two sides of a debate.  It seems revolutionary what Fox has done to TV news - present two sides of a story.  Some people become terribly wound up over this.  On a personal note, I have an "ultra liberal" uncle, by his own definition, that in all honesty is so upset over Fox news and me watching it that he no longer communicates with me.  Uncle Gordon probably has never watched Fox News.  He only knows what he has heard.  And knowing him if he did watch he would only see the conservatives and not notice the liberal view point.  I hope one of these days he calms down and we can find ourselves on friendly terms again.  Change is hard for some to come to terms with.          

    When reading this blog, it disturbed me.  I wish that all news reporters tried harder to present two sides to a story. These high radiation reports would be easy to demonstrate as being only half true.  But instead, because of poorly researched, unprofessional reporting, there undoubtedly will be Americans that will decide to not have a life saving CT heart scan for fear of radiation poisoning.  And that is sad.

  • Dr. Davis

    7/22/2007 3:09:00 AM |

    Hi, JT--

    I couldn't agree more.

    If there's one theme that presents itself over and over lately, it is the struggle to discern the truth in the sea of information we're all presented with every day. I can only hope that we all zig-zag towards a real truth over time.

  • Darwin

    7/24/2007 6:34:00 PM |

    Re the CTCA - new study out concerning radiation exposure for young women.

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