low-carb diet

Health & Fitness News: Pain Science, Breakfast – To Skip or Not to Skip?, Carbs vs fat (Whither protein?), 8 Glasses of Water Mythology

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Several articles have grabbed my attention. One is a concise summary of the current understanding of pain. Another discusses breakfast and the flimsy evidence supporting its importance. Next, science looks at the efficacy of reducing carbs vs fats for weight loss. Finally, drinking eight glasses of water a day is based on nothing.

Pain and lifting

The issue of pain is a continual theme in this blog. I’ve dealt with periodic bouts of lingering pain. The upside to this is that I’ve learned a lot about pain. Whether we’re an athlete or not, most of us will encounter non-acute or chronic pain.

It can be scary and depressing to us especially if it limits our ability to train. Interestingly, learning about how pain works can actually help us feel better (low-back pain in this case). Pain is NOT simply an indication of tissue damage. It’s very much a product of the brain. How we perceive our bodies (damaged or strong), our pain (threatening and scary or just a nuisance) and our expectations (“I’m broken and ruined,” or “I’ll be fine.”) are major influences on the pain process.

In that direction, Elitefts.com has a worthwhile article called 3 Things Lifters and Coaches Need to Know About Pain. It’s concise and fairly easy to understand for non-scientists. I think this information is useful for coaches and trainers who will certainly come across an athlete or client in pain. It may also prove helpful to you if you’re in pain. Here is a summary:

1. You are not your MRI or your X-Ray. Many people have tissue damage or degeneration on imaging but walk around without pain everyday. If you’re dealing with pain or an injury, get a thorough medical history and functional examination done by a qualified health professional, preferably one that works with athletes and lifters (they are out there).

2. Understand that pain (particularly chronic pain) isn’t purely related to biomechanics or injury. Biological and psychosocial factors both contribute to a person’s pain experience.

3. When working with clients, don’t create fear or a nocebo effect by berating your clients on their lifting technique, posture, or movement capabilities. Instead, work through your client’s issues with positive coaching and cueing to build a great training effect.

Read the article to get more detail.

Breakfast and weight loss

“Breakfast is the most important meal of the day.”

You’ve heard it. You believe. I’ve preached it to clients. It seems the earth rotates around this statement. But, is this bit of gospel based on anything of substance? Not really.

In The science of skipping breakfast: How government nutritionists may have gotten it wrong the Washington Post discusses research that shows the following:

“In overweight individuals, skipping breakfast daily for 4 weeks leads to a reduction in body weight,” the researchers from Columbia University concluded in a paper published last year.”

Another golden idol knocked from its pedestal! How can this be? Why would the USDA Dietary Guidelines for Americans tell us something that isn’t supported by good evidence?

The Post article does a good job of discussing the answer.

One of the key pieces of evidence, for example, examined the records for 20,000 male health professionals. Researchers followed the group for 10 years and published results in 2007 in the journal Obesity. They showed that after adjusting for age and other factors, the men who ate breakfast were 13 percent less likely to have had a significant weight gain.

“Our study suggests that the consumption of breakfast may modestly lower the risk of weight gain in middle-aged and older men,” the researchers said.

The advisory committee cited this and similar research, known as “observational studies,” in support of the notion that skipping breakfast might cause weight gain. In “observational studies,” subjects are merely observed, not assigned randomly to “treatment” and “control” groups as in a traditional experiment.

Observational studies in nutrition are generally cheaper and easier to conduct. But they can suffer from weaknesses that can lead scientists astray.

One of the primary troubles in observational studies is what scientists refer to as “confounders” — basically, unaccounted factors that can lead researchers to make mistaken assumptions about causes. For example, suppose breakfast skippers have a personality trait that makes them more likely to gain weight than breakfast eaters. If that’s the case, it may look as if skipping breakfast causes weight gain even though the cause is the personality trait.

It’s a reminder of the very important rule: Correlation doesn’t equal causation. Just because one detail appears alongside another detail, it doesn’t mean the one detail causes the other. (Tall people play basketball. Therefore one might conclude that playing basketball makes people tall. Is that right?)

Similarly we’ve seen a recent revision on dietary fat and cholesterol guidelines. We once thought that fat (particularly saturated fat) and cholesterol were the most evil of edible substances. Based upon flawed science, we were told to replace fat with carbohydrates and we’d all be well. Upon further review, it seems we may have been very wrong.

Low-carb vs. low-fat

Sticking with the diet and science theme, there’s been a lot of discussion on a recent study in Cell Metabolism that looks at low-carb vs. low-fat diets. This was a six-day study in a carefully controlled lab environment. The study had the same group of 19 obese participants spend six days on either a restricted-carb or restricted-fat diet. They then went home for several weeks for a “wash-out” period where they resumed their normal eating habits. The participants then returned and they were switched to the other diet. The same number of calories were cut from both diets, the difference being the calories came specifically from either carbs or fat. The participants were observed in a metabolic chamber and their caloric expenditure was very closely monitored. It was a well-designed study.

The result? The low-fat group lost more fat. Discussion over right? If you saw most of the popular-press headlines you’d think so. But there’s more to the story.

First question in my mind is “What about protein?” Though the jury is still out on some aspects of high-protein diets, several studies (here, here, here and here among others) suggest that high-protein diets can be useful for weight loss. The study doesn’t mention protein at all. Seems odd to me in that carbs, fat and protein are the main macronutrients in food. Why would we want to manipulate and study the effects of just two?

A good discussion of the low-carbs vs. low-fat study can be found at Examine.com. Really-low-fat vs somewhat-lower-carb – a nuanced analysis goes into some of the limitations of the study. This article is quite detailed. Read it all if you’re up for it. I won’t go into all of it but here’s a little bit.

One point to remember that this low-carb diet could be called a “lower-“carb diet in that some low-carb diets go much lower than this one. The Examine.com article says:

“The carb levels ended up being 352 grams for Restricted Fat versus 140 for Restricted Carb, and the fat levels 17 versus 108. In other words, (moderately lower carb than typical diets) versus (oh my goodness I can count my fat gram intake on my fingers and toes!).

This trial wasn’t designed to explore a real-life 100-gram-and-under low carb diet and especially not a ketogenic diet. Rather, it was a mechanistic study designed so that they could reduce energy substantially and equally from fat or carbs, but without changing more than one macronutrient. If they lowered carbs much more in the Restricted Carb group (like under 100 grams), they’d then have to go into negative fat intake for the Restricted Fat group. And negative fat intake is impossible (*except for in quantum parallel universes). One more note: all participants kept dietary protein constant and exercised on a treadmill for an hour a day.”

So it’s possible that if carbs were lowered further, we might see a different outcome of the study. Also, this was a six-day study. We must wonder what might happen over the course of six weeks, six months or six years.

Another very important point to remember is that this was a very tightly controlled experiment. It didn’t reflect the real world in which people trying to lose weight have to make their own food choices. Examine.com says:

And to repeat a very important point: this study was not meant to inform long-run dietary choices. In the long-run, the choice between restricting fat or restricting carbs to achieve a caloric deficit may come down to one thing: diet adherence.

While preference for certain foods may dictate which diet is easier to adhere to, this isn’t always the case. For instance, it seems that insulin-resistant individuals have an easier time adhering to a low-carbohydrate diet. Nowadays, new dieters often pair low-carb with higher protein, the latter of which can boost weight loss. And since there are plenty of high-sugar but low-fat junk foods (see Mike and Ike, et al.) but not so many high-fat but low-carb junk foods, low carb intakes can sometimes mean an easier time staying away from junk food when compared to low fat diets.

So we should remember that the dietary rubber meets the road when someone seeking weight loss can modify their diet in any healthy way and then stick to it for the long haul. If it’s less fat then great. If it’s fewer carbs, also great. If it’s some other improvement to the diet then wonderful!

Eight glasses of water a day is arbitrary

Another sacred cow of health and longevity is the admonition to drink at least eight glasses of water a day. That bunk has been debunked but much like a bell that’s been rung, it’s hard to change people’s minds once they’ve heard this information. The New York Times gets into this topic in No,You Do Not Have to Drink 8 Glasses of Water a Day. This one is simple. If you’re thirsty then drink. If you’re not then don’t. (How else would we have made it to the year 2015 if we didn’t have some sort of very good water gauge built into our physiology? Do my cat or dog think about the measured quantity of the water they drink?)

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Are All Calories Created Equal?

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“Put most simply, the fewer carbohydrates consumed, the more energy these weight-reduced people expended.”
Gary Taubes, author, Good Calories, Bad Calories

A recent Harvard University study has produced some interesting results as regards various types of eating patterns, calories, and how these all affect weight loss maintenance.   The study is discussed in two New York Times articles; one titled What Really Makes Us Fat, the other titled In Dieting, Magic Isn’t a Substitute for Science is a Q&A with a veteran obesity researcher. ABC News also analyzes the study in For Calories, It’s All About Quality Over Quantity, Harvard Study Says.

There are two main points of consideration in this discussion.  First, there’s the question, “Are all calories created equal?”  Are carb calories the same as fat and protein calories?  Are refined sugar calories the same as calories from vegetables or beans?  The second question is, “What’s the best way to stay lean once we’ve lost the weight?”

(The country is full of people who’ve lost weight but can’t keep it off.  The big secret is this: Any diet will work.  If you follow the directions, you’ll very likely lose weight no matter what diet you chose.  From paleo, to the Zone Diet, to Weight Watchers to any of the vast number of other diets, if you follow it you’ll probably lose weight.  Done and done?  No. The most difficult part has just begun.  Keeping the weight off is typically very difficult.)

What about the study?  Researchers studied 21 overweight and obese adults, starting each on a diet that helped them lose about 12-13% of their body weight. Then, to help them maintain that weight loss, the researchers put the participants on a cycle of three diets, each lasting four weeks.

One diet is of the low-fat/high-carbohydrate variety as advocated by the FDA and the American Heart Association.  This diet suggests among other things that we eat a lot of grain products, both refined and unrefined; and that we seek to reduce fat consumption at all opportunities.

The other diet was a high-fat/low-carbohydrate diet similar to the Atkins diet.  This is almost the total opposite of the previously mentioned diet.  This diet encourages fat and protein consumption and discourages grain consumption–particularly refined grains.

The third diet was based on low-glycemic foods.  This diet was sort of in between the other two. Fewer refined grains were found here and more vegetables, beans, fruit and the like.  Plus there was less fat and protein than the Atkins-type diet, but more than the low-fat diet.

What were the results?  This is from the ABC News article:

The results weren’t good news for low-fat diet aficionados. When dieters followed that plan, their bodies burned fewer calories than when they were following the low-carb or low-glycemic index diets. And the low-fat diet changed certain metabolic factors in their bodies that typically predicted weight regain.

The low-carb diet seemed to help participants burn the most calories. But it also increased certain markers of stress and inflammation in the body, such as the stress hormone cortisol, which are risk factors for cardiovascular disease and other health problems.

(I’m quite curious about this.  What’s causing the inflammation?  Is it high fat?  Is it high protein?  Is it low carbohydrate?  Is it a combination of some or all of these factors?  The Perfect Health Diet discusses research indicating that limiting protein intake can help with immune function, and that too much protein can lead to ammonia toxicity.  So that leads me to think it’s the protein that may be causing the inflammation.  Would someone please do a double-blind placebo study on this?  And please make it a long-term study while you’re at it.  Thanks in advance.)

In the end, the researchers found that the low-glycemic index diet struck the right balance for the participants. It helped the dieters burn more calories, though not as many as the low-carb diet, but didn’t seem to increase disease-causing stress markers in the body.

I like this observation as well:

“Remember the old food pyramid, with six to 11 servings per day of bread, pasta or rice at the base? In light of this article, it would seem to provide an efficient prescription for weight gain,” said Dr. Jana Klauer, a doctor in private practice in New York.

Gary Taubes, says in What Really Makes Us Fat:

The results were remarkable. Put most simply, the fewer carbohydrates consumed, the more energy these weight-reduced people expended. On the very low-carbohydrate Atkins diet, there was virtually no metabolic adaptation to the weight loss. These subjects expended, on average, only 100 fewer calories a day than they did at their full weights. Eight of the 21 subjects expended more than they did at their full weights — the opposite of the predicted metabolic compensation.

(Please note that Taubes is the author of Good Calories, Bad Calories.  He essentially proposes some of what is suggested by this study, namely that a high-carb diet–particularly one high in refined carbs–is bad and that a high-protein/high-fat diet is good for us.  His article for the NY Times highlights the good of this diet.  He doesn’t mention the following information.  Perhaps there’s a conflict of interest.)

Now, here’s a wrinkle.  Dieting, Magic Isn’t a Substitute for Science is the other NY Times article. It’s a Q&A with Dr. Jules Hirsch, emeritus professor and emeritus physician in chief at Rockefeller University, who has been researching obesity for nearly 60 years, about the state of the research. With regard to the benefits of high-fat diets, he says:

They report that people on the Atkins diet were burning off more calories. Ergo, the diet is a good thing. Such low-carbohydrate diets usually give a more rapid initial weight loss than diets with the same amount of calories but with more carbohydrates. But when carbohydrate levels are low in a diet and fat content is high, people lose water. That can confuse attempts to measure energy output. The usual measurement is calories per unit of lean body mass — the part of the body that is not made up of fat. When water is lost, lean body mass goes down, and so calories per unit of lean body mass go up. It’s just arithmetic. There is no hocus-pocus, no advantage to the dieters. Only water, no fat, has been lost.

The paper did not provide information to know how the calculations were done, but this is a likely explanation for the result.

So the whole thing might have been an illusion? All that happened was the people temporarily lost water on the high-protein diets?

Perhaps the most important illusion is the belief that a calorie is not a calorie but depends on how much carbohydrates a person eats. There is an inflexible law of physics — energy taken in must exactly equal the number of calories leaving the system when fat storage is unchanged. Calories leave the system when food is used to fuel the body. To lower fat content — reduce obesity — one must reduce calories taken in, or increase the output by increasing activity, or both. This is true whether calories come from pumpkins or peanuts or pâté de foie gras.

To believe otherwise is to believe we can find a really good perpetual motion machine to solve our energy problems. It won’t work, and neither will changing the source of calories permit us to disobey the laws of science.

So Dr. Hirsch draws a different conclusion from the researchers and the reporters.  I don’t have a solid enough command of statistics to advocate in either direction.  Both Dr. Hirsh and Gary Taubes suggest that more useful information would come from a long-term study of this type.

What seems clear though is that we should steer well clear from processed foods.  A high-fat/low-carbohydrate diet seems to best best for weight loss but also may cause an increase in the stress hormone cortisol.  The study suggests that making an extra effort to avoid fat may not be very helpful in the battle to rid our bodies of fat.  The third and possibly healthiest eating strategy revolves around a healthy intake of low-glycemic foods.  The Wiki entry on low-glycemic foods states (emphasis is mine):

There are some specific factors to look for in foods that can indicate their glycemic index: Low glycemic foods contain: Fat, Whole grains, Protein, Raw Starches, legumes, vegetables, fruits and dairy products. High Glycemic Foods contain: Refined grains, refined sugars, increased amylopectin: amylose ratio, and often high sugar fruits have a high glycemic index.

Finally, we’re often told to eat more of this that and the other.  “Eat more healthy fat.”  “Eat more fruits and vegetables.”  “Eat more whole grains.”  We’re rarely told to “Eat less” of anything. Therefore I like what Dr. Hirsch has to say about the matter:

What would you tell someone who wanted to lose weight?

I would have them eat a lower-calorie diet. They should eat whatever they normally eat, but eat less. You must carefully measure this. Eat as little as you can get away with, and try to exercise more.

 

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