The other day at work, we got to talking about foods which promote fitness and Larry mentioned that he had read a new study about caffeine. He didn’t go into it much at the time, but I was curious since I gingerly sip caffeine every morning (tea — Earl Grey — hot). So, later that day, I went to see what I could find at the Health section of Google News.

Sure enough, researchers at Duke University did a study of caffeine’s effect on blood sugar levels. They tested 14 people with type 2 diabetes and discovered that large doses of caffeine can cause blood sugar levels to climb:

The study showed that caffeine had little effect on glucose and insulin levels during the fasting period, but it caused significant surges after eating a meal. People who received the 375-milligram dose of caffeine experienced a 21% larger increase in glucose levels and a 48% larger increase in insulin levels compared with those who took the placebo during the two hours following their meals.

“It seems that caffeine, by further impairing the metabolism of meals, is something diabetics ought to consider avoiding. Some people already watch their diet and exercise regularly,” says Lane. “Avoiding caffeine might be another way to better manage their disease. In fact, it’s possible that staying away from caffeine could provide bigger benefits altogether.” […]

It’s not that caffeine creates blood sugar, but it seems to aggravate blood sugar levels when consumed with a high-carbohydrate meal. So, I may be out of the woods on this one — I generally have a mid-carb breakfast of diced apples with cottage cheese (+ cinnamon + Splenda) but I drink my tea about an hour after I eat breakfast. With any luck, most of my breakfast-based blood sugars would have been metabolized by then.

The Center for Science in the Public Interest — a Washington-based think tank which focuses on food and nutrition — is urging the FDA to require restaurants to disclose the use of trans fats. I don’t always agree with the CSPI, but I’ll concede that they may be on point this time.

In case you’re not up to speed on trans fats, they’re a type of fat (like saturated fat or monounsaturated fat) but far worse than other types of fat since they not only raise your “bad” cholesterol but they also lower your “good ” cholesterol. They’re created by the hydrogenation of liquid oils (turning them solid) and commonly used by restaurants for frying.

The FDA is requiring food labels to include trans fat by 2006, but that still doesn’t help much with restaurants. And, as much as I respect a restaurant’s artistic license to design their menu as they like, I’m not sure that artistic license outweighs the health concerns in this case.

So, I think the CSPI may be on to something here. Then again, I don’t agree with everything they have to say. One of their side-projects is TransFreeAmeria, an effort to ban trans fat entirely. And, while trans fat is undeniably unhealthy, I still believe that people should have the choice to consume whatever they like, whether bad for them or otherwise.

I’ve been reading off and on about interval training which, in short, is cardio training with short intervals of intense effort. I was browsing through some magazines at Barnes & Noble and a recent mention in Men’s [Health | Fitness] reinterested me in the technique. I checked online for some more information and found some useful articles at iVillage.

From what I've read, interval training can burn more calories in less time than traditional cardio. And the article “Invigorate with Interval Training” at iVillage has a good overview. As a starting point, they define exertion on a 1-10 scale with 1 being “very easy” and 10 being “very difficult”; and, they offer various interval training suggestions depending on your current fitness level:

• For beginners, they recommend a 1:3 ratio of interval (at exertion 4-5) to recovery (at exertion 2-3). So, after a warm at low-middle effort for 5 minutes, you could go to a half-full effort for 2 minutes, return to low-middle effort for 6 minutes, and then repeat with the interval.

• And, for intermediate fitness, they recommend a 1:1 radio of interval (at 4-6 exertion) to recovery (at 2-3 exertion). This one does have the advantage of being the easiest to keep track of times ;).

• Then, for conditioned folks, their recommendation goes back to a 1:3 interval-to-recovery ratio, but with an interval intensity around 7-10. They point out that these intervals are called “anaerobic, because they are more like sprints and can't be sustained for a great amount of time on the aerobic energy system”.

Much of their examples focus on treadmills, but they add that easily adaptable to other machines such as exercise bikes and elliptical machines. I’ve been aware of interval training intuitively for some time, but I haven’t known the particulars on ratios and exertion. And, as I’ve only heard good things about this technique, I look forward to giving it a try next time I go to the gym.

New Scientist reports on two new studies on the health effects of low carb eating. As with previous studies, the participants lost weight without harmful effects on blood fats and sugars:

Stern’s year-long study […] was twice the length of any previous study. Half the patients followed the Atkins regime, limiting daily carbohydrate intake to just 30 grams. The rest tried losing weight through a conventional low-fat diet much richer in carbohydrates.

By the end, both groups had lost about the same amount of weight, between five and eight kilograms for the Atkins group and three and eight kilos for the low fat group. But the Atkins dieters lost almost all their weight in the first six months, then remained at a steady weight. […]

I found it interesting that the low carb eaters lost most of their weight in the first six months (and leveled off from there). Some news articles covering the studies stressed this point, as if to imply that low carb eating wasn’t effective. However, the participants kept the weight off for the duration of the study.

I was also pleased to read that the low carb participants showed lower levels of triglycerides — a type of fat in the bloodstream which may lead to obesity.

Compared with the low-fat group, Atkins dieters also had lower levels of triglycerides, potentially harmful blood fats which can trigger heart disease. Concentrations of beneficial high density cholesterols (HDLs) also held up better in the Atkins group. And these favourable changes remained till the end of the study, suggesting that there might be lasting benefits. […]

A second study run by Duke University Medical Center has similar findings to the first, though low-carb eaters lost about twice that (12 kg) of those in the study eating low-fat foods. However, a “substantial number” of the low-carb dieters also saw increases in their bad cholesterol — but I’m not sure to what degree that’s relevant since the article doesn’t elaborate on the phrase “substantial number”.

Researchers at Saint Louis University have discovered what may be one of the primary causes of obesity. The hormone leptin normally tells the brain to stop eating but triglycerides may block leptin from reaching the brain:

The scientists used mice to look at how leptin, a hormone secreted by fat cells that tells us to stop eating, gets into the brain. They found that in obese mice, high triglycerides, a type of fat in the bloodstream, prevents leptin from getting into the brain, where it can do its work in turning off feeding and burning calories.

“High triglycerides are blocking the leptin from getting into the brain. If leptin can’t get into the brain, it can't tell you to stop eating,” says Banks, who is principal investigator and a staff physician at Veterans Affairs Medical Center in St. Louis. […]

Before reading about this study, I hadn’t even heard of triglycerides. But, this sounded like a significant discovery and so I looked for more information on them. And, I found this page at the Duke Student Health Center which offered some tips on lowering triglycerides:

Lifestyle changes are the key to change:

• Reduce intake of saturated fat and cholesterol in your diet. (saturated fat should account for no more than 7-10% of total calories and cholesterol intake should be reduced to < 300mg/day).
• Increase physical activity to 30 minutes of moderate intensity activity on most days.
• Increase intake of monounsaturated and polyunsaturated fats such as those found in canola oil, olive oil and nuts, while decreasing intake of saturated fats such as those found in butter, red meats and bakery foods.
• Consume the majority of your carbohydrate calories in the form of whole grains, vegetables and fruits.
• Keep in mind that substituting carbohydrates for fats may actually raise triglyceride levels and decrease HDL levels in some people.
• Include fish high in Omega-3 fatty acids at least 2 times per week. Fatty fish such as salmon, swordfish, mackerel, and sardines are good sources of omega-3 fatty acids.

After reading more about it, I feel better about my triglyceride outlook — I watch my saturated fat intake, I eat fish (a tuna sandwich) every day, and I exercise regularly. And now that I’m aware of their impact on general health, I’ll keep an eye open for more research on triglycerides.

I was reading an issue of Wired’s dead tree edition that a friend had given me and they had a sidebar (not really a full article) on new sugar substitutes. The usual suspects such as aspartame and sucralose were there, but they also had high praise for one called tagatose which they described as “subtle & natural”. So, I checked online for more information and — go figure — found a Wired article on tagatose.

Like Splenda, tagatose is made from sugar, but tagatose is derived from milk sugars within whey. And, though Splenda already tastes very natural, apparently tagatose is virtually imperceptible from sugar. The only downside is that tagatose isn’t calorie-free — it has about 1/3 the calories of sugar. But, it doesn’t affect blood-sugar levels or cause cavities.

Levin whips out a set of keys, unlocks his desk, and rummages through a drawer. He pulls out a bag of tagatose-coated bran flakes and a chocolate bar, both creations of his Danish licensee. The bran is a little stale but sweet enough, and the chocolate tastes just like the real deal. He hands me a baggie of pure tagatose. I hold it up to the light, dab a little on my finger, and try it. A dead ringer for table sugar. […]

Though it’s not a calorie-free food, I’m still excited about another sugar substitute. With any luck, this will soon find its way into reduced-calorie chocolate bars and sodas (Spleda-based chocolate still doesn’t quite taste like the real thing). However, it appears that the tagatose folks don’t have quite the marketing arm of their Splenda counterparts; so, I have a hunch that it may be a while before tagatose becomes widespread.

The Atkins folks have long spoken against the USDA Food Pyramid — I’m not a particular fan of it either and, indeed, the government plans on revising it by early next year. However, the Atkins group decided not to wait that long and they released their own food pyramid.

As you might expect, this pyramid has protein sources on the bottom tier (“eat more”) and grains at the top tier (“eat fewer”) — almost the opposite of the USDA version. Interestingly, even though a geometric food summary such as this may seem to oversimplify an eating plan, this one actually clarifies many aspects.

For one thing, many people think of Atkins as all “meat and cheese”. But, a quick look over their pyramid would show that’s not really the case — cheese is on the second-to-the-top tier, only just below grains. Many people also overlook the diet’s vegetable component. Veggies such as broccoli, cauliflower and asparagus (all of which are considered healthy on just about any diet) are on the second tier, just after protein sources.

I was also impressed that one of their footnotes emphasizes that hydrogenated oils should be avoided. Otherwise known as trans fats, they’re a rather bad type of fat as they not only raise your bad cholesterol but also lower your good cholesterol (even saturated fat doesn’t effect good cholesterol).

I don’t follow Atkins; rather, I go with The Zone which has a 40/30/30 ratio between carbs, protein & fats. All the same, Atkins seems a little more reasonable each time I learn more about it.

The Chicago Tribune is reporting that the Department of Agriculture is revising the ubiquitous food pyramid for release early next year. The article’s subtitle reads “The revised pyramid will likely offer 12 diet plans; the current one offers only three” — I wasn’t even aware that the current one had three versions. And in addition to more variations, they have other changes planned as well:

For instance, sedentary men between ages 31 and 50 would be urged to quadruple their consumption of dark green vegetables and legumes, triple the amount of whole grains they eat and double their intake of orange vegetables. They would also be encouraged to cut their consumption of starchy vegetables such as potatoes and solid fats by half. […]

Though I’m a bit concerned that the food industry will meddle with the final result, the proposed changes seem to make sense so far. “Cutting consumption of starchy vegetables” — hmm, where have I heard that before? ;) Kidding aside, I think the reduction in solid (saturated) fats is probably also a worthwhile recommendation.

The New York Times reports that Atkins Nutritionals is now recommending that people on their diet limit saturated fat to 20% of their calories. They’re trying to play this off as a clarification, but it sounds like a revision to me :-/.

Responding to years of criticism from scientists that the Atkins version of a low-carbohydrate, high-fat regimen might lead to heart disease and other health problems, the director of research and education for Atkins Nutritionals, Colette Heimowitz, is telling health professionals in seminars around the country that only 20 percent of a dieter’s calories should come from saturated fat. Atkins Nutritionals was set up by Dr. Robert C. Atkins to sell Atkins products and promote the diet. […]

Revision or otherwise, I view this as a positive move as many had dismissed the diet due to its lack of restrictions on saturated fat. For those already on the diet (which doesn’t include me), I was curious about how much saturated fat that would allow in a day…

Supposing a caloric intake of 1500 Calories, 20% would be 300 Calories from saturated fat. And, with 9 Calories/gram, 300 Calories would be about 33g saturated fat. So, to keep within 33g, you could eat:

• Breakfast Sausage Links — about 5 (6g saturated fat each).
• Breakfast Sausage Patties — about 6 (5g saturated fat each).
• Bratwurst Links — about 3 (9g saturated fat each).
• Pepperoni Pizza — about 6 pieces. (5g saturated fat per slice)
• All-the-Meats Pizza — about 4 pieces. (7g saturated fat per slice)

But, don’t let the numbers fool you — those calculations are for an entire day’s worth of fat. For instance, if you were to have three bratwurst, that would leave virtually no fat for the rest of the day. But, you can mix-and-match to evenly distribute your saturated fat allowance (which works out to about 10-11g saturated fat per meal).

And, if you’re on Atkins, you can stay under your limits by eating other sources of protein such as chicken or fish. Just checking my freezer downstairs, I see that trimmed boneless/skinless chicken breast has less than 1g saturated fat per serving. Likewise, canned tuna also has less than 1g saturated fat. Mayo has about 1.5g/TBsp, so a tuna salad could work also.

Fortune magazine has a feature they call Atkins World which nicely sums up the low-carb phenomenon over the past year. There's not much about the science of the diet but more of the culture surrounding it and its effect on various industries (like as bread & pasta). Much of it I was already aware of (such as the increase in egg consumption), but there were a few surprises as well.

[spoilers ahead] If you want to be surprised, don’t read this part. Most starting to me was the news about Splenda. Most people are probably aware that Splenda is in products such as Diet RC, Ocean Spray Lite and Blue Bunny ice cream. But, I was astonished to read that Diet Coke in Japan has Splenda! I'm guessing that even Larry may not have been aware of that one ;). In any case, if Coke has formulated Diet Splenda Coke and dispersed it to Japan, I can only hope that the US will have it soon. [/spoilers]

Most amusing to me, though, was some of the dedication that some of these low-carb companies have — to taste as well as nutrition:

[…] And that’s how [Keto] CEO Arne Bey wants it. For the past five years his passion has been to make low-carb food with the taste and texture of regular food. “When I hear, ‘It’s not that bad,’ it pisses me off,” Bey says, offering a visitor a chocolate Keto shake in lieu of lunch. […]

For what it’s worth, there’s also a print version of the article which doesn’t require clicking from one page to the next.