Diets don't work for you? How about fasting?

I was interested to see this new study in the American Journal of Clinical Nutrition which found that an alternate day fasting technique helped people lose weight and improve their cholesterol profiles.

I've talked about the pros and cons of modified fasting for weight loss before and in the last year I've been experimenting with this technique for some of my nutrition counseling clients. This study confirms my own observation: For some people, eating very little some of the time is easier than eating a little less all of the time.

In this particular study, the participants ate whatever they wanted every other day. On the days in between, they ate a single mid-day meal which provided about 25% of their normal calorie needs. At the end of eight weeks, the participants had lost about ten pounds a piece, lowered their body fat by about 6%, and also lowered their total and bad cholesterol.

Is fasting easier than dieting?

Here's what's especially interesting to me: The subjects were able to stick to the diet just as well when they were on their own as they were when their fast-day meals were provided as part of the study.  

What do you think? Would it be easier for you to cut way back on calories every second day if you knew you could basically eat what you wanted the next day?  It seems to be an effective way for overweight people to drop a significant amount of weight.

Modified fasting could also be adapted as a long-term maintenance strategy as well. You might find, for example, that you can avoid regaining the weight by fasting one day a week and eating ad libitum the rest of the days.

Your thoughts?

Vitamin D deficiency doesn't "explain" kidney disease

The winner of this week's Most Misleading Medical Headline Award is:

Low Vitamin D Level Explains Most End-Stage Renal Disease Risk in African Americans

I beg to differ. 

African Americans are more likely to have low vitamin D levels. They are also more likely to suffer from kidney disease. The correlation between these two facts appears strong. However, this "explains" nothing.  There's no evidence to show that vitamin D deficiency causes kidney disease--nor any proposed mechanism to explain how it might do this. And, as the investigators themselves point out, no evidence that raising vitamin D levels will reduce this risk.

Maybe I need to create a new category for these posts: Good research, badly reported.

High and low carb diets equally effective...as long as someone else is in charge

We've been talking a lot on the blog lately about quality vs. quantity of calories.  On one end of the spectrum are those who insist that weight loss (or gain) is simply a matter of quantity: It doesn't matter whether you eat protein, fat, complex carbs, or sugar; if you simply eat fewer calories than you burn, you will lose weight. 

On the other end are those who believe that quality is the key: you can eat as many calories as you want without gaining weight as long as they are the right kind of calories (i.e. protein and fat rather than refined carbohydrates).  

Those in the second camp spend a lot of time talking about how refined carbohydrates stimulate insulin release which promotes fat storage, while protein increases thermogenesis and fat-burning.  But I think the magnitude of these metabolic effects is greatly over-stated. 

I suspect that the real "magic" of the low-refined-carb diet is that it tends to regulate calorie intake.

Refined carbohydrates tend to stimulate appetite and lead to over-consumption. But what if you take appetite out of the equation.  What happens when someone else decides what and how much you eat? Consider this recent study: 

After losing an average of 36 pounds on a weight loss program, obese subjects were put on one of two weight maintenance regimens: one was high protein and the other high in carbs.  A year later, both groups were equally successful in maintaining their weight loss. The researchers concluded that "the protein or carbohydrate content of the diet has no effect on successful weight-loss maintenance."  

When calories and macronutrients are "tightly controlled," the metabolic magic of the low-carb diet is undetectable.  This would seem to support my suspicion: The primary advantage of the low-refined-carb diet is not that it recalibrates the body's metabolism and tendency to store or burn fat, but that it reins in appetite, thereby reducing calorie intake. Nothing wrong with that!

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Strange Science: Meat consumption increases risk of Type 2 diabetes

A new meta-analysis concludes that a diet high in meat increases your risk of Type 2 diabetes by 17%.  Eating a lot of so-called "red" meat was associated with a slightly higher increase (21%), and a high intake of processed meats increases your risk by a whopping 41%.

Media reports are quick to point out that this is just the latest in "an ever increasing list of bad news for red and processed meat."

In all of these studies, the division of meat into "red" and "white" seems totally arbitrary, as I discussed at length in this post: Meat and mortality: What does color have to do with it? 

In this particular case, the authors concede that the apparent association between meat consumption and diabetes risk could be explained by other factors. (So why exactly are we going to press with this result?)

A false association seems even more likely in this case than in the recent associations between meat intake and cancer risk or all-cause mortality.  At least there are plausible mechanisms to explain why high meat intake might increase cancer risk. For example, charred meat contains known carcinogens--although I hasten to point out that this has nothing to do with the "color" of the meat.

Diabetes is a disease of disordered carbohydrate metabolism. Meat is made up of protein and fat. How could eating more protein and fat increase the risk of diabetes?  Doesn't it seem more likely that there is something else about the lifestyle or dietary habits of people who eat large quantities of meat (especially processed meat) that might increase their diabetes risk? Are they also over-weight? Are they sedentary? What's their consumption of alcohol? Of high-glycemic foods? 

I'm keeping an open mind but pending more convincing data, I'm not sure I'm buying it.

Reality Check: Does candy turn kids into monsters?

Trying to rein in the amount of sugar kids eat is hard enough.  Having a plastic pumpkin full of candy in the house sure doesn't make it any easier.

There are plenty of compelling reasons to limit kids' intake of sugar. Candy is a source of empty calories that can displace more nutritious foods, lead to weight gain, and wreak havoc with insulin metabolism. (Type 2 diabetes used to be called Adult Onset Diabetes, but no more.)

But many parents are also convinced that sugar turns kids into little monsters--making them hyper-active, aggressive, or otherwise unmanageable. Yet the research fails to bear this out.

Is it all in parents' heads? 

Controlled studies have measured the effects of sugar consumption on behavior and cognitive performance and failed to find any connection. See for example this meta-analysis. There have even been interesting studies where parents were asked to observe kids behavior. When the parents thought the kids had eaten sugar, they reported changes in behavior--even when the kids had actually been given a placebo. See this article for more on the sugar-hyperactivity myth.

Just last month, there was an interesting new twist on this: Researchers found that kids who ate candy every day were more likely to be arrested as adults for crimes involving violence, as reported by AP News. The researchers hastened to add that the association is probably more complex than it sounds. It may be, for example, that individuals with poor impulse control eat more candy as kids and then commit more crimes as adults. 

What's a responsible parent to do?

Most parents settle for damage containment and try to strike a balance between nutrition concerns and letting kids enjoy this once-a-year festival. Rather than banning all Halloween candy (now who's the monster?), try to limit the amount that is collected and then dole it out slowly.  One small treat after a healthy meal isn't going to turn your kids into monsters.  Getting your kids up and moving--whether it's to rake leaves, play touch football, or even some Wii tennis--is also an effective way to mitigate the effects of a little extra sugar.  

Can you absorb fat-soluble vitamin D from skim milk?

Q. I recently read that Vitamins A, D, E, and K are fat soluble, meaning that they dissolve in fat instead of water. Does this mean that these vitamins need to be eaten with some type of fat source for the body to absorb them? For instance, if somebody ingested just a cup of skim milk would any of the Vitamin D not be absorbed because of the lack of fat?

A. It's not so much that fat-soluble vitamins dissolve in fat, but that they are carried across the intestinal cell barrier by lipid (fat) molecules.  So, while it is true that fats are necessary for transport and absorption of fat-soluble vitamins, it doesn't take much!

A couple of years ago, there was a study that found that eating avocado with vegetables increased the absorption of fat-soluble beta-carotene from the vegetables. However, a study that looked specifically at vitamin D found that vitamin D was absorbed just as well from both skim milk and orange juice as it was from whole milk. (Maybe the fiber in the vegetables plays a role somehow?)

The most likely causes of fat-soluble vitamin deficiency includea missing or malfunctioning gall bladder, bariatric (weight loss surgery), intestinal resection, or other serious digestive diseases that interfere with absorption of fats.

Homocysteine and heart disease

You don't hear a whole lot about homocysteine these days but ten or fifteen years ago it was quite the buzzword in nutrition and preventive medicine circles--and a cash cow for nutritional supplement sellers.

A little background on the homocysteine hypothesis

Population studies (aka epidemiological studies) showed that people with high levels of homocysteine in their blood had a higher risk of heart disease. Homocysteine is an amino acid which is an normal byproduct of protein metabolism. Ideally, it is further converted into another amino acid, methionine. However, if this "recycling"  breaks down, homocysteine can build up in the blood. 

When the link between high homocysteine and heart disease risk was noticed, researchers theorized that homocysteine might irritate the blood vessel lining, leading to injury, inflammation, and the formation of arterial plaques.

Certain B vitamins (B6, B12, and folic acid) act as co-factors in the conversion of homocysteine to methionine. Further research confirmed that those with high homocysteine tended to be low in one or more of these nutrients. Taking the next step, it was established that supplementing with these nutrients reliably reduced elevated homocysteine levels. It seemed all but certain that this would in turn lower heart disease risk.

Hold that thought

However, the homocysteine hypothesis recently took a big hit, in the form of a meta-analysis of eight studies involving some 24,000 subjects. The upshot? The authors found “no evidence that homocysteine-lowering interventions, in the form of supplements of vitamins B6, B9 or B12, given alone or in combination, at any dosage compared with placebo or standard care, prevents myocardial infarction, stroke, or reduces total mortality in participants at risk or with established cardiovascular disease.”

Ouch.

Those in the business of selling nutritional supplements are crying foul, claiming that the conclusions are "misleading."  Read responses from the Health Food Manufacturers’ Association (HFMA) and the International Alliance of Dietary/Food Supplement Associations (IADSA).

It's possible that those with very high homocysteine levels have more to gain than those with only mildly elevated levels--and that the meta-analysis obscures this reality. The meta-analysis also failed to evaluate whether B vitamins could prevent healthy people from developing heart disease. But, coming from organizations who profit from sale of dietary supplements, I find this argument less compelling.

I'm curious: How many of you have had your homocysteine levels tested? How many of you take B vitamins specifically to manage homocysteine levels? Share your comments below.

Do overweight people eat less than thin people (or do they just think they do)?

A lot of people are excited about Gary Taubes' book Good Calories, Bad Calories, which claims that weight loss or gain has nothing to do with how many calories you eat but how much refined carbohydrate you eat. I heard Taubes present his ideas at a conference last year and he makes some great points. Ultimately, I agree with his conclusion--over-consumption of refined carbohydrates is a primary cause in today's epidemic of "diabesity."

But I think he over-argues his case--and some of his arguments about how and why carbohydrates lead to obesity are flawed.

For example, as proof that excess calories are not the cause of weight gain, Taubes cites studies showing that that overweight people eat the same or less than thin people. Here's the problem: The studies he cites use self-reported intake records. We know that overweight people consistently under-report the number of calories they eat. (Here's yet another study measuring this.) The more overweight you are, the more you tend to under-report.

In fact, when you put overweight people into controlled (i.e. in-patient) settings and feed them the number of calories they think or say they are eating, they reliably lose weight--regardless of whether they are eating refined carbohydrates or not. (Whether this weight loss is sustainable in the real world is another question).

I think it's more accurate to say that refined carbohydrates seduce us into eating more calories than we need.  They taste good, you can consume a lot of calories before you get full, and you're hungry again sooner than you would have been had you eaten proteins, fats, or non-refined carbs. Excess calories = weight gain.

Eliminating or reducing refined carbohydrates may help realign your appetite regulation systems with your actual energy needs.  Reduced calories = weight loss.

Did the Dairy Council set the RDA for calcium?

Q. The RDA for calcium seems impossible to achieve unless someone eats dairy (or takes supplements), but considering that dairy has been part of the human diet for only a short period of time (and most people are lactose intolerant), how can our requirements really be that high? Is there scientific evidence that we need that much calcium or has the Dairy Council had a hand in the government's guidelines?

A. You mean, was there a conspiracy to get Americans to consume more dairy products by setting the recommendations for calcium intake higher than necessary? I wouldn't go that far (although I'm sure some would!).

The RDA for calcium reflects the realities of the typical Western diet

The RDA for calcium represents the amount that will meet the needs of most (97%) healthy individuals. They're taking into account not only the amount needed to prevent acute calcium deficiency but also to prevent long-term consequences like osteoporosis.

This is based on scientific research, of course. But most of that research is done on people who eat a typical Western diet--which is relatively high in both protein and sodium. Coffee and soft drinks (containing caffeine and phosphates) are frequently consumed.  All of these things can increase the body's calcium requirements.

The RDA for calcium reflects how much calcium it takes for someone with a typical Western diet to maintain adequate calcium stores.  Those on a lower protein or lower sodium diet might require less.

Non-dairy sources of calcium

Not only are dairy products some of the richest sources of dietary calcium, but the calcium in dairy is well absorbed by the body. But if you're not into dairy, canned salmon and sardines are great non-dairy sources. Tiny bones in the fish--so soft that they're simply consumed with the flesh--are what makes these fish good calcium sources.  Kale and collard greens are also good sources. A cup of collards has as much calcium as a cup of milk.

Is vitamin D your best protection from swine flu?

Dr. John Cannell is convinced that the swine flu epidemic could be vastly curtailed with vitamin supplementation.  (Cannell is the Executive Director of the Vitamin D Council, a non-profit organization dedicated to educating the public about the perils of vitamin D deficiency.)

Anecdotal reports support vitamin D as flu preventive

Cannell has been campaigning to get the NIH and CDC to investigate claims that vitamin D supplementation (2,000 to 5,000IU per day) confers virtual immunity against swine flu.   As evidence, he presents reports from two physicians, one from a long-term care facility in Wisconsin and one with a private practice in Georgia. Both doctors use aggressive vitamin D supplementation with their patients--and both report that their patient populations were virtually untouched by flu when it swept through their facilities and practice communities. You can read testimonials from the physicians on the Vitamin D Council website.

As supporting evidence, Cannell notes that vitamin D is involved in immune response and that low vitamin D status appears to increase one's susceptibility to respiratory infections.  Some researchers theorize that the reason that the flu season tends to peak in winter is that this is when most people's vitamin D levels are lowest. (This was not the case with H1N1, however, which had a robust summer season.)

Are public health officials dropping the ball?

So far, neither the CDC nor the NIH appear interested in investigating this further, although Canada's public health agency is adapting its current study on vitamin D and influenza to include the H1N1 virus.

But with H1N1 breathing down our necks, the results of this and other research will come far too late to protect us from this year's swine flu threat. Cannell argues that people have nothing to lose from vitamin D supplementation and much to gain.

Some researchers fear vitamin D could backfire

But is there really nothing to lose from vitamin D supplementation? An group of researchers from the U.S. and Australia isn't so sure. Their research suggests that vitamin D supplementation may actually suppress immune response. Interestingly, increasing vitamin D levels by exposing the skin to sunlight or UV-B rays does not appear to have this immuno-suppressive effect. (Here's a link to their entire paper, published in Autoimmunity Reviews.)

Since this paper was published earlier this year, I've been eager to hear some sort of response or analysis from Cannell and the crew at Vitamin D Council but haven't seen anything from them yet.I can see why the CDC is not ready to jump on the vitamin D supplement bandwagon quite yet.

What's your best move?

Where does this leave us in regard to this flu season? I think people (and their physicians) are going to have to weigh the evidence--all of which is preliminary--and decide for themselves whether the potential benefits outweigh the potential risks.  

Perhaps the best compromise is to get as much vitamin D as possible through natural sunlight. As we get into winter (here in the Northern hemisphere), your best bet at stimulating vitamin D production is to get outside at mid-day and bare as much skin as you can.  For those who missed it, here's a calculator that will help you calculate how many minutes a day you'd need to cover your vitamin D requirements.

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