How Related Are Weight And Health?
August 14, 2008
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The conventional wisdom is that if you are normal sized you are healthy and if you are overweight you are unhealthy. However, a recent analysis has suggested that it is not that simple and that weight and health may not be related in a straightforward way.
More data from NHANES (National Health and Nutrition Examination Survey) suggests that some “normal weight” people are unhealthy and that some people considered overweight do not have signs of cardiac disease or other diseases that have been conventionally associated with obesity.
Of course being thin has never necessarily meant healthy. For instance, my mother who suffers form Crohn’s disease is thin due to her disease. However, in this analysis of the NHANES surveys, of those with normal weight there were a significant proportion who had what the authors called “metabolic markers of obesity”.
What were considered to be metabolic markers of obesity? They included high blood pressure, elevated triglycerides, high fasting blood glucose, high levels of C reactive protein (hsCRP) and low levels of HDL (the good) cholesterol.
The proportion of normal weight people with these markers increased with age, from 10.3% for ages 20 to 24 years , 16.9% between 35 and 49 years, 41.7% between 50 and 64 years, 54.7% between 65 and 79 years, and 56.2% 80 years and older.
Conversely, for those considered overweight and would be expected to have the metabolic markers, there were many who were in the optimal range. Healthy levels of the markers decreased with age, but represented a substantial proportion of the survey participants. The ranges were 47.7% between 20 and 34 years, 31.1% between 35 and 49 years, 20.4% between 50 and 64 years, 14.3% between 65 and 79 years, and 22.1% 80 years and older.
This sort of goes against what we are told. It will be interesting to see how the discussion of the data develops. The data does suggest that you need to go and get tested for cholesterol, glucose, triglycerides etc, whatever your size. Find out what your numbers are, then go from there.
Technorati Tags: weight, metabolic, obesity, NHANES
Popularity: 11% [?]
Low Fat vs. Low Carb vs. Mediterranean Diet
July 19, 2008
A new study compared low fat, low carb and Mediterranean diets. The findings were that those on the low carb and Mediterranean diets, lost more weight and had more improved cholesterol and triglyceride levels, than those on the low fat diet.
The study was conducted at a remote nuclear facility in Israel, so there was control over the diets of the participants. There were many more men than women in the study, so the findings for women may be less general. The low fat and Mediterranean were calorie restricted, the low carb diet was not calorie restricted.
All dieters lost weight, but those on the low fat diet lost the least. Men lost most on the low carb diet, whereas women lost most on the Mediterranean diet.
HDL cholesterol (the good cholesterol) increased most on the low carb diet, closely followed by the Mediterranean diet and the worst was the low fat diet. LDL cholesterol (the bad cholesterol) decreased the most on the Mediterranean diet, the low carb diet was intermediate and there was only a small decrease on the low fat diet. Triglycerides dropped most with the low carb diet, the Mediterranean diet had a slightly small drop and the low fat diet had a much smaller drop.
These results suggest that low carb and Mediterranean diets may be more effective than a low fat diet both for weight loss and improving cholesterol and triglyceride levels.
Since the low carb and Mediterranean diets are almost equally effective, then choosing the diet that suits your tastes and lifestyle, is going to be what is most successful.
The study is published in the New England Journal of Medicine 359:229-241, 2008.
photo credit: sethschoen
[tags]low fat, low carb, Mediterranean, diet, weight, cholesterol, triglycerides[/tag]
Popularity: 33% [?]
Leptin Might Be The Key To Weight Loss and Maintenance
June 25, 2008
One of the problems when dieting is that after the while the body adapts to the lower calorie intake. After a period of restricted food intake the body starts to make changes in some of its systems.
When calories have been in short supply for a while, the body increases the feelings of hunger. This is a basic survival mechanism and would make our prehistoric ancestors go out and find some berries or go hunting a woolly mammoth. We need to eat to survive. Unfortunately dieting also triggers this survival mechanism, and stimulates an overfeeding response.
Additionally, after a period of restricted calories our metabolism slows down. This, too, is a survival mechanism. In times when there is a shortage of food, if the amount of energy that the body uses can be reduced, we are more likely to survive until there is adequate food again.
These two changes in the body result in it becoming harder to lose weight after dieting for a while. Importantly, it also makes it harder to maintain the weight loss after losing the desired weight.
Leptin is a hormone that is secreted by fat cells. It is involved in a number of processes in the body including energy regulation. During fasting, the levels of leptin circulating in the body drop. This drop in leptin levels has a range of effects that include reduced energy expenditure and the stimulation of overfeeding.
Several studies suggest that a potential treatment option for weight loss and maintenance may be leptin or some future drug that increases the levels of leptin. The studies looked at both energy expenditure and brain activity in response to food stimuli.
The first studies compared markers of energy expenditure, with and without, an injection of leptin under the skin for those on a weight loss program. The leptin injection increased the circulating leptin levels to those pre-diet, and at the same time increased the levels of the markers of the body metabolism. So increasing the levels of leptin reversed the slowing of the body metabolism. This is likely to increase the rate of weight loss, and be important for weight maintenance.
The second study looked at brain activity. In certain areas of the brain after being on a diet for a while there is increased activity, which correlates with an increased appetite. In those who received leptin, the brain activity decreased to the level found prior to dieting. This suggests that increased leptin levels may decrease the feelings of hunger and make overfeeding episodes less likely.
These studies have several potential implications. As stated above, would treatments that increased leptin levels be useful in the latter stages of weight loss and for weight maintenance? (Note: The majority of obese individuals have high levels of leptin and are leptin-resistant so treatment is unlikely to work for them, unless they are on long term calorie restriction. For those who are obese and have low leptin levels, it certainly could be a treatment option.) Additionally, do low levels of leptin predict obesity later in life? Would measurement of leptin levels help target those who have a high likelihood of gaining weight?
It is likely in the future that some form of leptin therapy may be of benefit to a significant number of people, particularly for weight maintenance.
The research has been published in the Journal of Clinical Investigation and is authored by Rosenbaum et al. For more details there is an excellent free access commentary in the issue as the most recent article.
Technorati Tags: leptin, weight loss, weight maintenance, slow metabolism, appetite, overeating
Popularity: 37% [?]
High Carb, High Protein Breakfast For Weight Loss?
June 23, 2008
Should breakfast be a high carb, high protein meal and then the remaining meals low carb, low calorie? A new study suggests that this might be the way to lose and maintain weight loss.
Carb restriction has been shown to be an effective method of dieting. However, there are two common problems. First, it is hard to maintain for extended periods of time, due to the intense carb cravings that most people get. Secondly, once a low carb diet is stopped, there is often a rapid weight gain.
The idea of high carb, high protein breakfast diet is that it reduces the cravings for carbs and increases the sense of fullness. This will then make sticking with the diet easier and not lead to the rebound effect of “carb cramming” after stopping dieting.
A yearlong study compared a low carb diet (not the high protein, high fat Atkins-style) with a diet that had a high carb breakfast. The focus for the first 8 months of the study was weight loss, the next 4 months focused on weight maintenance.
The results are very interesting. After 4 months the low carb only group had lost an average of 28 lbs and the high carb breakfast group had lost an average of 23 lbs. However, at 8 months the low carb group had regained an average of 18 lbs, whereas the high carb breakfast group had on average lost another 16.5 lbs!
The authors suggest that “The big-breakfast diet works because it controls appetite and cravings for sweets and starches. It also is healthier than an extremely low-carbohydrate diet, because it allows people to eat more fruit and therefore get enough fiber and vitamins.”
Sounds worth a try since the usual low carb diet does not seem to work long term for the majority of people.
This study was presented last week at the annual Meeting of The Endocrine Society. The press release gives more details including the number of calories, carbs, proteins and fat.
Technorati Tags: low carb, high protein, breakfast, weight loss
Popularity: 42% [?]
Sleep More And Weigh Less?
April 8, 2008
By one of those stranger than fiction coincidences when I woke to my radio alarm clock this morning the feature was on sleep and weight. “Sleep more and weigh less”, filtered into my brain. I thought did I really hear that right? Surely you need to be up and doing stuff to lose weight.
As I fully focused on the radio, I heard somebody repeat it, and say that it does sound counterintuitive. So I decided to take a look at the topic of sleep and weight.
This is what I found out. Those that slept less than 8 hours in duration had on average increases in BMI (body mass index) proportional to amount of sleeping they were missing.
Recently studies in humans have demonstrated that sleep restriction or deprivation results in a “dysregulation” of appetite control and increased hunger. In other words, those that were sleep restricted had bigger appetites, were hungrier and ate more. Further, there were changes in glucose tolerance so the sleep restriction was bad for diabetics.
Why should this be? Sleep regulates a number of hormones. Included in these hormones are leptin and ghrelin, both of which are involved in appetite. Leptin is also involved in control of energy expenditure. Sleep restriction decreases leptin levels, which causes an increase in appetite and a decrease in energy expenditure (metabolic levels). Sleep shortage increases levels of ghrelin which results in both more food intake and fat deposition. The changes in both these hormones will have a negative impact on food consumed and fat accumulation.
So control of appetite and an increased metabolic rate are two more very good reasons to get a good amount of sleep every night.
Abstract for a review article about sleep and body function.
photo credit: CraigGrocott
Technorati Tags: sleep restriction, sleep deprivation, appetite, hunger, leptin, ghrelin
Popularity: 49% [?]
The Brain Can Sense Calories
March 27, 2008
This is not good news! Independent of taste, the brain can sense calories. This means that eating is not just driven by taste. This may give clues as to why high fructose corn syrup consumption is linked to obesity.
Studies showed that mice genetically engineered to not be able to taste sweet, still preferred sugar solutions over those that contained a non-calorific sweetener. Analysis of the brains showed as in normal mice the “reward circuitry” was switched on in the brains of the non sweet tasting mice, when they drank sugar solutions. So the mice could somehow sense the sugar independent of taste.
This awareness of calories means that the body can somehow sense the calorie content of at least some foods. This ability was probably important for primitive humans, when we were assessing which foods were best to eat for energy for hunting etc.
Now the ability to sense calories and get pleasure from them is bad news for most of us, since it may encourage us to keep eating, well after our calorie requirements have been met.
This may have implications for the link between consumption of high fructose corn syrup and obesity. As stated in a commentary on the research it has been shown that, “evidence suggests that fructose is not as effective as sucrose in terminating a meal. It may be that fructose produces stronger activation of the reward system and that removing high-fructose corn syrup as a sweetener will curb some desire for these products.”
With our current lifestyles and the wide availability of food, sometimes I think we are just doomed.
The study is in Neuron 57: 930-941, 2008 and the commentary in Neuron 57: 806-808, 2008 (not indexed by PubMed yet, so references are not linked).
photo credit: Uwe Hermann
Technorati Tags: brain, calories, high fructose corn syrup, food reward
Popularity: 88% [?]
Wow! A Fat Reduction Cream That Does Work
February 26, 2008
A new study looked at whether applying a fat reduction cream containing aminophylline worked. Participants in the study had a BMI of greater than 27, and were told to follow a 1,200 kcal diet. Additionally some of the participants were told to rub 0.5% aminophylline cream on their waist twice per day.
By week 12 of the study there was a difference in the waist measurement between the groups. All study members lost inches from their waists, but those using the cream lost more. The difference was an average of 11 cm (4.3 in) for those using the cream, and an average of 5 cm (2 in) for those who did not use the cream.
There was no difference in the change in BMI between the two groups. What changed was the waist to hip ratio, which is a measurement of body shape. So those that used the cream changed from more apple shape to pear shape, which reduces the risk of a number of diseases including diabetes and cardiovascular disease.
So amazingly it looks like local application of fat reducing cream containg aminophylline cream may work.
I looked around to see who sold cream containing aminophylline. The best deal I could find was on Amazon for BodyLift Anti-Cellulite Thigh Cream Extra Strength reduced to $8. I hate under my chin, so I am going to try it to see if I can reduce my double chin. For $8 I don’t think I can go wrong.
The study was published in the journal Diabetes, Obesity and Metabolism the abstract is available at PubMed.
Technorati Tags: weight reducing cream, aminophylline, BMI, waist to hip ratio
Popularity: 78% [?]
Metabolic Syndrome, Chew (Drink) On It
February 10, 2008
Yesterdays post Weight Training Revs Up Body Metabolism brought to mind the recent finding that drinking diet soda increases the risk of metabolic syndrome. A large number (9,500, aged 45 to 64) of people were followed for nine years. One of the findings was that the risk of getting metabolic syndrome was a whopping 34% higher in those who drank diet soda. This was a higher risk than those who ate a “nutritionally poor” diet, whose risk increased 18%. It is amazing that diet soda had a higher risk.
We hear about metabolic syndrome all the time. I would bet that most people have absolutely no idea how it is defined; they just know it is not good. These are the clinical guidelines from ATP III. Clinically you are classified as having metabolic syndrome if you have 3 or more of the following; a) waist bigger than 40 inches (men), or 35 inches (women); b) triglycerides 150 (mg/dL) or greater; c) HDL cholesterol 40 (mg/dL) or less (men), or 50 (mg/dL) or less (women); d) blood pressure 130/85 (mmHg) or greater, for either number; e) fasting glucose 110 (mg/dL) or higher. So now you know.
Drinking diet soda is one of the few bad habits that I don’t have. For some reason diet soda gives me a stomachache. I wonder if my body thinks it is getting a rush of sugar, and then when it finds it has been fooled, extracts its revenge. Perhaps one of the few times that my body has done me a favor.
The study was published in Circulation (pubmed)
Technorati Tags: metabolic syndrome, diet soda
Popularity: 75% [?]
Flying and deep vein thrombosis (DVT)
February 1, 2008
I hate flying. I got back last night from England, where I was visiting my parents. By the time I got home I felt, and looked like, an old rag that had been in the tumble drier for days, with the heat setting alternating between hot and frigid.
My food intake on the flights was appalling; banana bread, something I think was apple pie, twix, shortbread, very greasy ravioli and stale bread rolls. However, I could at least take comfort in the fact that I was unlikely to get deep vein thrombosis (or DVT). I wore my DVT socks and got up and walked around periodically. In Europe there seems to be much more concern and press coverage about DVT. For instance, in England you can buy DVT socks for travel in any regular supermarket.
DVT or deep vein thrombosis, sometimes called deep venous thrombosis, is the formation of a blood clot in a deep vein. When flying, due to sitting with out moving and dehydration, there is an increased risk of formation of a clot in the legs. Sometimes this is called economy class syndrome. There is a possibility that a clot could travel up to the lungs and cause a pulmonary embolism, which is bad news. This blockage of an artery to the lungs can cause difficulty breathing, chest pain and can in severe cases cause loss of consciousness and even death.
DVT often has no obvious symptoms. Swelling of one or both legs and pain and redness may occur for some people but usually it is silent.
DVT socks are compression socks or stockings. They are a gentler version of the stockings that you have to wear after surgery, if you are going to have to remain in bed for a day or two while recovering.
There have been a number of studies including Lancet, 12:185, 2001 looked at two groups of passengers on long flights, where half the study participants wore DVT hosiery. The Lancet study demonstrated that 10% of the people in the study who did not wear DVT socks, had asymptomatic (no symptoms) DVT. None of those wearing DVT socks had DVT.
So for long haul flights get yourself some knee high travel compression stockings and get up and walk around a couple of times to reduce the risk of DVT.
Technorati Tags: deep vein thrombosis, DVT, flying, economy class syndrome, compression socks
Popularity: 86% [?]
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