Obesity, Inflammation, and Diabetes

This entry is cross posted from the the SITN Flash, a bimonthly publication written and edited by Harvard graduate students. You can find my piece, as well as archives of previous articles written by many graduate students at the Science in the News website.

In 1985, the Centers for Disease Control (CDC) began tracking the prevalence of obesity in the United States. Since then, a clear trend has emerged: obesity is on the rise. The maps below compare obesity levels across the United States in 2004 and 2008:

Obesity 2004 vs 2008

It's clear that the number of people with obesity is growing, and has been as long we have been tracking it.

Obesity is defined as having a body mass index (BMI) over 30. BMI is calculated by dividing your weight (in kilograms) by the square of your height (in meters). It is important to note that BMI is by no means a perfect measurement of health - its correlation to body fat can vary depending on one's physiology and genetics - but it is the easiest and least invasive way to assess body fat percentage. More accurate measurements can be achieved by measuring relative buoyancy (fat is less dense than other body tissues) or by looking at tissues with X-ray or MRI, but these methods require special tools and a visit to a doctor [3]. To give you an idea of what obesity by BMI means, someone six feet tall would be classified as obese if they weigh over 220 lbs, someone 5'6" would have to weigh over 185 lbs, and someone five feet tall would be over 150 lbs to be considered obese by this measurement [4].

Obesity affects more than the size of your waistline. If you're wondering why the CDC is tracking obesity, it's because those excess pounds have been linked to several significant health problems, including heart disease, stroke, and some forms of cancer. In fact, one study in 2009 estimated that the direct medical cost of obesity in the US accounted for $147 billion of total health-care spending. Of all the health problems associated with being overweight, one of the most significant and well-studied impact is the increased risk for diabetes. Compare the following maps charting the percentage of adults diagnosed with diabetes from the same time span as the previous maps:

Diabetes Figure.png

The rates of both obesity and diabetes are rising all over the country, and regions with the greatest increases in levels of obesity have corresponding increases in diabetes. In addition to the strong geographical correlation, there is solid evidence for the role of excessive weight in diabetes, but we are only recently beginning to understand the mechanism behind this link.

Diabetes: The Disease

Diabetes mellitus is the Latin name for two conditions in which people are unable to regulate their blood sugar. Blood sugar is comprised of the simple sugar glucose, a product resulting from the breakdown of food that we consume and digest. In healthy people, blood glucose levels are controlled by two competing hormones. When glucose is low (for example, after not eating for awhile), the hormone glucagon is released and causes cells to break down and release their stored glucose. When blood sugar goes up after a meal, the pancreas releases insulin, signaling cells to absorb glucose from the blood and rebuild their stores [5]. Normally, these two processes are finely tuned to make sure cells have sufficient stores of glucose, but are also ready to release it when necessary. In diabetic patients, however, the insulin response is defective, and blood sugar can get dangerously high. In fact, the term diabetes ("passing through" in latin) mellitus ("sweetness") refers to the fact that blood sugar levels are so high that glucose is excreted in urine.

The two forms of diabetes have similar symptoms but have two different root causes. Type 1 diabetes is the result of an inability to produce insulin. Often, this is because the body's own immune cells attack the β-islet cells of the pancreas - the sole producers of insulin. This is an example of an autoimmune disease, and is thought to be unrelated to diet and lifestyle.

Type 2 diabetes is far more common, accounting for nearly 90% of all cases of diabetes, and is the form of the disease that has been linked to obesity. Type 2 diabetics are able to produce insulin, but their cells are unable to respond to it.

Today, diabetes can be effectively managed with the use of synthetic insulin injections, but this requires constant vigilance. If blood sugar levels aren't managed properly, the medical complications can be severe and widespread. Chronic high blood sugar can damage blood vessels, increase a person's risk for heart attacks and stroke by two to four times compared to a non-diabetic person, and can result in significantly higher blood pressure. Blood vessel damage can be so severe that it can lead to blindness and nervous system damage or cut off blood flow to the lower limbs, necessitating amputation [6].

Inflammation, Obesity, and Diabetes

Though aberrant immune responses have long been associated with type 1 diabetes, recent evidence has begun to mount that inflammation and the immune system is also heavily involved in type 2 diabetes. Inflammation is the immune system's normal response to infection. Immune cells called macrophages can detect the presence of bacteria and viruses, and release signals that alert the rest of the immune system to an invading bug. These signals are called cytokines, and they promote an anti-pathogen response by increasing blood flow to the infected tissue, recruiting other immune cells from the blood and activating other, more potent immune cells. These activities result in the characteristic redness, swelling and pain associated with inflammation.

One of the first suggestions that the immune system was involved in type 2 diabetes came in 1993, when researchers at Dana Farber Cancer Institute in Boston, MA noticed an increased production of inflammatory cytokines in obese rats that are prone to diabetes. These cytokines were produced directly by adipocytes, the cells that store fat. Interestingly, when cytokine activity was blocked, these rats became less resistant to insulin and their blood-sugar levels dropped [7].

Since then, the evidence for the role of the immune system in the link between obesity and diabetes has continued to mount. In addition to their role in immunity, macrophages are also involved in maintaining healthy tissues and clearing debris. Macrophages in fat tissue are responsible for cleaning up after adipocytes that have burst and released their fat molecules, but in obese individuals, the increased number of adipocytes can overwhelm macrophages. In the last decade, several published studies showed that obese animals and humans have increased numbers of macrophages in their fat tissue, and that these macrophages were more prone to promote inflammation than the macrophages in non-obese individuals. More recently, the cytokines produced by these macrophages have been shown to have a direct effect on insulin resistance [8].

This research is already leading to potential treatments. Several promising anti-inflammatory drugs are presently undergoing clinical trials, and earlier this year, a study in mice showed that a drug currently used to treat arthritis may help decrease insulin resistance. These drugs may be expensive, however, and may not reach the general public for a long time. Until scientists find an affordable and effective treatment, the best way to prevent diabetes is to maintain a healthy weight. A recent study predicted that if current trends continue, 83 percent of men and 72 percent of women will be overweight or obese by 2020. As good as the science gets, we may not be able to make headway against this disease without changing people's behavior.


[1] Centers for Disease Control and Prevention: National Diabetes Surveillance System. Available online at: http://www.cdc.gov/diabetes/statistics/index.htm

[2] http://apps.nccd.cdc.gov/DDT_STRS2/FAQ.aspx

[3] http://en.wikipedia.org/wiki/Body_fat_percentage

[4] http://www.nhlbi.nih.gov/guidelines/obesity/bmi_tbl.htm

[5] http://www.endocrineweb.com/conditions/diabetes/normal-regulation-blood…

[6] http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002194/

[7] G.S. Hotamisligil, et al. Adipose expression of tumor necrosis factor-α: direct role in obesity-linked insulin resistance. Science, 259 (1993), pp. 87-91.

[8] Jerrold M. Olefsky and Christopher K. Glass "Macrophages, Inflammation, and Insulin Resistance." Annual Review of Physiology Vol. 72: 219-246 March 2010

[9] http://clinicaltrials.gov/ct2/results?term=anti-inflammatory+diabetes

[10] Daniel A Winer et al. "B cells promote insulin resistance through modulation of T cells and production of pathogenic IgG antibodies." Nature Medicine 17, 610-6187 (2011).


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Hi Kevin -

Have you seen any of the studies on developmental programming of obesity and/or metabolic syndrome? The findings are both beautiful and terrifying. I hate the somewhat deterministic nature of the findings, but the data is the data.

Maternal Obesity and Developmental Programming of Metabolic Disorders in Offspring: Evidence from Animal Models (Experimental Diabetes Research Volume 2011 (2011), Article ID 592408)

Fetal programming of adipose tissue: effects of intrauterine growth restriction and maternal obesity/high-fat diet (Semin Reprod Med. 2011 May;29(3):237-45. Epub 2011 Jun 27)

There are a ton more.

Clearly sedentary lifestyles and food options are big problems, but I fear that we may have a generation of children for whom the deck is heavily stacked against them from the first days of life.

- pD

Okay, sure, there may be some temporary fluctuations in body mass, but there's no reason to think humans are causing it. It could just be some trend in the movement of fatness... or something.

@ pD - I haven't read those studies in detail, but I'm aware of the implications. You're right that we may have a generation of children with the deck stacked against them - all the more reason to do everything we can to promote healthy lifestyles for everyone.

It's not going to be easy though.

@ Surgoshan - I see what you did there. My money is on sun spots.

that is a rather dramatic increase in 4 years. The map of change since 1990 is also pretty amazing. I remember people's lifestyles in the 90s, and it is hard to believe that people are eating much more poorly now than then. Unless I was to learn that the addition of the internet has completely reduced the average exercise level, it does seem like an outside factor is influencing the map

@ July - Inactivity is a problem too. The same place survey that looks at obesity and diabetes also looks at physical activity. Take a look. The changes aren't as dramatic, but they're there.

Great article!
Wow, those 2020 statistics are scary!
Activity and healthy diet, those are our two trusted and true allies. However, there is so much confusion and misinformation on the internet now that I think it actually sends people in the wrong direction, making things worse.
Hopefully we can get our act together soon to better the health of our nation. Thanks for your article!
-Mandy Seay, RD, LD

Ho, Ho, Ho! Merry Christmas! An article just in time to meet the jolly fat man!

By Mike Olson (not verified) on 21 Dec 2011 #permalink

Perhaps I am mistaken, but aren't obesity rates increasing in most industrialized societies? The reason I bring this up is in regards to prepared or "manufactured" foods- has there been any studies that have shown any major differences in the way they are made? I realize that of course we eat more of these types of meals now but I wonder if there are significant differences beyond that (beyond fat and sugars for example).

On a observational note, it is interesting to see video shot as late as the 70's and 80's and see how much thinner most people seemed to be.

Inflammation, driven by excess fat, underlies a lot of Western ills, particularly cancer.

BMI is, as you say, misleading. There's a simpler, non-invasive measure: the waist or its ratio to that of the upper thighs. This also relates directly to the most dangerous fat of all - visceral fat.

I think Dr Barry Sears (of the Zone diet and other research/books) has perhaps the best handle on this.

Get the waist circumference and the EFA ratios right (plus Vit.D3 & homocysteine levels) and most of the illnesses will reduce/disappear.

Type 2 diabetes can be cured by going on a two week 500 cals/day regime; and then staying off all carbs.

@ Kellym - Pam over at Tomorrow's Table or the guys at Obesity Panacea are probably better people to ask - I'm not really current on the literature regarding health and nutrition and what goes into those things. There's a reason I tackled this topic from an immunology perspective :-)

@ Ian - I'm not aware of the literature linking adipose inflammation to cancer. I'm not sure that waist to thigh ratio is actually easier than BMI - most people know their height and it's relatively easy to step on a scale. I think the CDC uses this measure because it's easier to standardize, and it's sufficiently correlated to health that it's worth knowing. It's certainly possible that they will include a few people that are healthy with a high BMI, and exclude people that are unhealthy with a lower BMI, but I think this measure is good enough to track what they want to track.

Just maintain a healthy weight, as if it were that easy. Go on a 500 cal a day diet? YOU try it. I have been involved in numerous weight loss groups over the years, and I can tell you that nobody struggles more or works harder to lose weight than those folks. It is so frustrating to hear people who have never had a weight problem speak as if they have the answers and they are "easy".

I challenge anyone who has not been on a diet to cut back 500 calories a day for 2 weeks and see how it feels. Try going to bed with your stomach growling every night and then we'll talk about weight loss.

@ Aggie - I don't think anyone is saying it's easy - I certainly didn't. I cut back to 2500k calories/day (which is roughly what my maintenance level should be) and it's incredibly hard. My mom has been struggling with her weight for decades, but recently found a diet plan that seems to be working for her. For anyone struggling to lose weight, I recommend taking a look at reddit.com/r/loseit - there are tons of inspirational stories, diet and exercise plans of all sorts and a really great community of people that can help.

500 cal/day is starvation, and I don't think that's the answer, but cutting calories and increasing physical activity is possible (not easy), and necessary for proper health. And ultimately, it's probably less effort in the long run than daily insulin shots and monthly doctor's visits.

I lost 1/3 of my body weight over a span of 9 months and have kept it off for a year. It involved a change in lifestyle. I switched to using smaller plates. I paid attention to serving portions. For example when cooking pasta I only cook 2 ounces per person. I reduced my food intake and dramatically increased my daily exercise. During the 9 months I kept my caloric intake to 1,200 to 1,500 calories a day and upped my exercise so I was exercising 500 to 1,000 calories a day. I lost 70 pounds so it is doable over 9 months. A big thing was stopping use of the car. I now no longer drive if I am only going up to 5 miles. I bicycle instead. I even bicycle sometimes if I need to go 10-15 miles one way. I have not been so healthy in years and I am in my mid 50s. Now maintaining my weight is easy.

I've lost some 40 pounds over the last several years and am still overweight. Major thing I did was quit eating between meals. I notice parents loading up kids plates and kids getting nothing but french fries on their own. I think a young child should be given very small portions, then given more if they want it. I see young kids not wanting to eat, perhaps because they are overwhelmed by the amount of food in front of them.

By Jim Thomerson (not verified) on 24 Dec 2011 #permalink

Pardon my having problem with the analysis, but I'm a little bothered by the two graphs each for obesity and diabetes are only four years apart, and that the white areas encompass a range of bmi's of 19.6 while all but the last category have bmi ranges of around 4 in obesity's case. Overall the increase looks dramatic, somewhat like the increase I would expect to come from a communicable disease rather than from a change in dietary habits. That is unless the development of diabetes follows a logarithmic curve rather than an arithmetic one or the disease has changed such that it now develops more rapidly in individuals than it used to.

By Steve Aronoff (not verified) on 24 Dec 2011 #permalink

You may be interested in the role that intracellular bacteria plays in disregulating the immune system, and the various hormone receptors (e.g. renin, thyroid, androgen, and the especially VDR which transcribes a plethora of antimicrobial peptides).

Cholesterol is not what causes heart disease. Food is not what causes diabetes or obesity.

Chronic diseases are now showing in newborns and children - they are not old enough to have developed chronic disease, but have had the same bacterial problem passed onto them by their parents.

The assumption that some causal event or environmental trigger makes the immune system to attack the body is wrong. The immune system is already in a serious state and the 'trigger' is simply the last straw.
This is why we are so confused and Koch's postulate is no longer valid. Is it Borrelia that causes lyme? Is is inhaled dust that causes sarcoidosis? Is it cholesterol that causes arterial sclerosis? Does alcohol cause cirrhosis?
Are genes responsible for cancer? The genes are the smoking gun, not the agent pulling the trigger.
Look further back up the trail of clues and see if you can see the pathogenic etiology that has already been identified.
Do conduct research, but not in a bubble of unawareness.

Some people that are obese are certainly to blame for their own state.

On the other hand, eating differently, or less and doing exercise is simply never going to help a large number of people, because that is simply not the cause of their obesity.

So many years, so many diets, so many exercise regimes - the evidence is clear that this does not work for a large percentage of people.

You are looking at chronic disease, which has been growing significantly over the last 80 years or so.

When almost half the population of the US is deficient in Vitamin D, ask yourself - is it REALLY because they're not getting enough? Almost every food product in the stores is supplemented with that same steroid that many people think is a vitamin that is going to be good for them.
The 'deficiency' is a marker, not a cause of disease.

@ Steve - No need to ask for pardon - it's a good idea to question the analysis of others. The way that you analyze numbers can often lead to erroneous conclusions, even if the underlying data is correct. If you go to the CDC's website (my first reference), they have graphs available that show the map by quartile rather than in this way. And if you dig a bit, all the raw data is available too, so you can plot it how you like. I agree that the increases are dramatic and unexpected, but the data is the data. If you do an analysis that you think is more representative, please come back and let us know.

@ arydberg - I didn't notice anything in that article that points to a government playing an active role, can you clarify?

@ Seth - You assert a number of things there without pointing to evidence (careful of putting in hyperlinks though, the spam filter will grab you). Let me take your points one by one.

You may be interested in the role that intracellular bacteria plays in disregulating the immune system, and the various hormone receptors (e.g. renin, thyroid, androgen, and the especially VDR which transcribes a plethora of antimicrobial peptides)

What intracellular bacteria are you referring to? It's not surprising that pathogens have an effect on the immune system, but are you claiming that people are obese because they are infected with a particular bug? And I'm unclear what all of those hormone receptors you listed have to do with anything.

Cholesterol is not what causes heart disease. Food is not what causes diabetes or obesity

There are direct links between some forms of cholesterol and heart disease, such as plaques on the walls of your blood vessels that increase blood pressure. Cholesterol isn't the only culprit of course, it's a complex problem. But we know that people with high cholesterol are at increased risk, and we know that lowering your cholesterol decreases risk.

Food does not cause obesity or diabetes. Eating too many calories and not exercising enough leads to obesity, and as I've recounted in this post, excess fat can lead to immune disregulation which can lead to diabetes. Again, these are complex issues, but you're making claims that go against the scientific literature that I'm aware of without pointing to any counter evidence.

Chronic diseases are now showing in newborns and children - they are not old enough to have developed chronic disease, but have had the same bacterial problem passed onto them by their parents.


This is why we are so confused and Koch's postulate is no longer valid. Is it Borrelia that causes lyme? Is is inhaled dust that causes sarcoidosis? Is it cholesterol that causes arterial sclerosis? Does alcohol cause cirrhosis?
Are genes responsible for cancer? The genes are the smoking gun, not the agent pulling the trigger.

It's not that Koch's postulates are no longer valid, it's that these postulates are only relevant for diseases that are caused by an infectious microorganism. Since this is not the case for, say, arterial sclerosis, it doesn't make any sense to try to apply Koch's postulates to that disease.

Cancer is an interesting case, since it's clear that some cancers can be driven by an infectious cause (like cervical cancer). However, cancer is an incredibly complex disease - even talking about "cancer" as some sort of monolith is misleading since there are so many different types of cancer, different disease progression, different risks and different causes.

Some people that are obese are certainly to blame for their own state.

On the other hand, eating differently, or less and doing exercise is simply never going to help a large number of people, because that is simply not the cause of their obesity.

I don't think blame is the right framework. But I also disagree with your assertion that eating less and getting exercise won't help a large number of people. Calories in < calories out will always lead to weight loss, though an individual's metabolism can have a significant impact on both sides of that ledger (it's not as easy as getting X amount of exercise and letting Y calories enter your digestive tract). The question is, what are the incentive structures that lead to the right behaviors. Right now, the cheapest food is the food most likely to lead to obesity, and getting exercise is hard.

When almost half the population of the US is deficient in Vitamin D, ask yourself - is it REALLY because they're not getting enough? Almost every food product in the stores is supplemented with that same steroid that many people think is a vitamin that is going to be good for them.
The 'deficiency' is a marker, not a cause of disease

I'm not really sure what you're trying to assert here. VitD is an interesting topic, as there is a lot of emerging evidence that deficiency is correlated with a number of problems that we aren't aware of. However, it's unclear what role supplementation will have in alleviating these problems. The jury is still out in my opinion.

But VitD is now considered a cure for a whole host of things by the alt-med community, so it's also hard to untangle the good evidence from the woo.

Everybody with a weight problem should try this for 2 weeks: Cut out most sweets and anything with wheat or corn in it. There's plenty of good stuff to replace these mostly empty calories - greens, veggies and fruit (mostly berries) for instance. I have lost 25 pounds over the past 6 months and I am almost never hungry. The first 10 pounds just melted off in a few weeks. Everyday aches and pains disappeared and mental clarity and focus are better than I can ever remember. I highly recommend Gary Taubes' Good Calories, Bad Calories and William Davis' Wheat Belly. The sooner the American public wakes up and recognizes the nonsensical dogma about "healthy whole grains" for what it is, the better.

By Wheatless (not verified) on 28 Dec 2011 #permalink

When I mention intracellular bacteria, I mean in particular, L-form bacteria. There is a huge amount of recent research and growing evidence that points to a pathogenic etiology for many chronic diseases. The stumbling-block, unfortunately, that must be overcome is the widespread current view that chronic disease has no infectious cause.

A direct link does not necessarily mean cause. A scientific paper may say, "A is linked with B", but this does not necessarily mean "A causes B", although this is a common misinterpretation by many readers and reporters in the media. Unfortunately, this simple misunderstanding is the reason that, despite recent research, for example, that many people now believe Vitamin D supplementation is going to help them avoid cancer or chronic diseases. The fact is, this has not been shown to be valid.

My point about cholesterol not causing disease is that it is not the agent of disease but merely a component.
When you talk of cholesterol, you should know that it is the building block for the hormones the body produces.
If it is taken up by a microorganism, metabolised and deposited as plaque in, for example, an artery, then is the cholesterol the causal factor? What is the agent of this deposition?
Brown dust is not the cause of a wooden house falling down, but if you look further back up the line of causality, you find termites.
If someone was to brick up the doors of your house, you would not say that the bricks were ultimately to blame for this problem, but the person that piled them there and applied the mortar.

There are several hormone receptors that are effected by the same molecules that are often introduced in the diet.
It does not make sense to measure, for example, serum thyroid levels and prescribe T3 or T4 to make up the balance (although, this is standard practice). Sure, it makes people feel better, but it doesn't attend to the underlying problem. If thyroid levels are out of range, there is going to be a reason.
An analogy is - if your car oil is low, you top it up, although another 100miles down the road you are going to have to top it up again, and again. The best solution is to fix the underlying problem. Perhaps the pistons are worn, causing the oil to be burnt, or there is a leak in the engine. Perhaps it is a slow leak that messes up your driveway, but you decide you can live with that. Perhaps the car is old and you don't plan on keeping it, then the trouble of a proper repair is unwarranted, so you just keep on topping up the oil until it finally gives in and the engine breaks down or you decide to trade it in on a new model.

We see too much of this in medical practice as 'disease care' rather than 'health care'. The disease is allowed for and people are palliated, putting off the need for a proper cure. If a doctor can make his patient comfortable with the diseease, then they are manageble until the last moments (although I don't see anyone with chronic dsease having final moments anything other than costly and/or painful).

Trying to regulate one hormone in the body is a fair effort, but many systems are inextricably linked. The balancing of one element can cause an imbalance of all the others, especially as they have common agonists and antagonists. You cannot simply regard one part and try and fix it without caring for the state of something else.
For example, if you were to cut a patient open to repair an artery, you would not forget to stitch them up afterwards. The dermis is just as important as the things it protects.

In 2011, a national cohort study of infants and toddlers found that nearly one-third of US children were overweight or obese at 9 months and 2 years old.
- Moss BG, Yeaton WH (2011). "Young Children's Weight Trajectories and Associated Risk Factors: Results From the Early Childhood Longitudinal StudyâBirth Cohort.". American Journal of Health Promotion 25 (3): 190â198.

Koch's postulate is simplistic and does not work when we start looking at chronic disease as having infectious cause. There is a huge amount of variety in every individual's microbiota, producing a range of symptoms which are classified as particular disease. That is, there is not a "one microbe - one disease" correlation. This is why we are failing repeatedly to identify one virus as a cause for ME or one bacterium as a cause Lyme, for example.

Also, what I am trying to point out is that immune dis-regulation already exists in an individual's system, before they put too much fatty food in their mouth, or before a deer tick triggers Lyme disease, or inhalation of 911 dust causes sarcoidosis.
There is an untold number of biofilms and microbes at work in your body and your particular microbiome is unique to you. This means that everybody has their own unique disease. Sure, doctors can attempt to categorise them, and many of them should be called syndromes rather than diseases - for example sarcoidosis is not regarded as having an infectious cause, although there is growing evidence to the contrary.
As you mentioned, there are many types of conditions that we refer to as 'cancer', but the truth is they are all unique diseases, brought about by the individual combined human-microbial organism. The extent of influence of the human metagenome is only beginning to be understood. (Of course, we know some cancers are caused by exposure to radiation or a genetic deformity).

Medicine to date is concerned with treating the human condition, and has been blind to the fact that on a cellular level, we are not 100% human - it is closer to 1%.

Read https://www.novapublishers.com/catalog/product_info.php?products_id=5380
Read Metagenomics of the Human Body (Springer).
Read the latest papers on Vitamin D, relating to protection against cancer and other diseases. Their only conclusions are that there is no clear supporting evidence and that 'further research needs to be done'. The problem is the press has already seized upon the hope that Vitamin D is the wonderful, sunshine drug that will help us be healthy. The truth is, it is not a vitamin but a steroid that palliates by supressing the immune system but at the same time, makes us more susceptible to disease. As long as you keep loading up on it, you may be ok, but if you try and wean yourself off, you better be aware of the consequences.

It is not hard to untangle the 'good evidence' from the woo. Read the published research.
When I say read the research, I am not going to give you links to papers - google can do that. As an academic, you have a responsibility to read and take into consideration work that has already been done in your field.
But the main drive must be that you are willing to do so. If you are going to discount anything outright, then you should not call yourself a scientist.

I could introduce you to many people I know personally who have exercised and dieted religiously but in vain to lose and keep weight off. The world is full of them - look around.
You have to start questioning all the repeatedly unsuccessful attempts and try and think differently. Don't go the same way everybody else has gone.
Medical science needs to experience something of a paradigm-shift if it is ever going to be able to discover as well as face the truth.

"Excess fat can lead to immune disregulation which can lead to diabetes"

Come on now, do you really believe excess fat disregulates the immune system?

Putting excess fat (even repeatedly) in a "type X" body may cause some weight gain but it does not make this person obese.
Putting excess fat into a "type Y" body where certain bacteria are present does cause fat to be retained and deposited in all the usual places.

Our metabolism is derived from not just the human part of us. The human gut is full of microbes that have a huge influence on our psychological and physical states, and each person has a different combination of pathogens, due to unique inheritance and exposure throughout a lifetime.

To say THE cause of obesity is too much fatty food and not enough exercise is ridiculous, especially if may be trying to explain it to a 9 month-old.

Yeah the data are the data, but the CDC's own data using actual measurements of height and weight isn't showing this increase. The maps take the weight and height that people report, giving results that are fairly wrong in general, and then cuts them into these BMI categories, which probably further distorts the results.

As an endocrinologist, I see the results of the research you just described. Type 2 diabetes was almost unheard of in children about 15 years ago. Now, the incidence of type 2 diabetes is starting to surpass the incidence of type 1 diabetes in children. I have also seen portion sizes getting larger especially in fast food restaurants. Parents need to learn how to feed their families and learn the composition of food and appropriate portion sizes as well. Nutrition used to be part of science classes taught in elementary school, and that component of education is now lacking. While some children get plenty of exercise, most are glued to the computer or TV and munch. We need more education about increasing activity, and proper eating in elementary schools and parents should be included in it.

Do not forget to factor in the damaging affects of FDA approved food chemicals which lead to inflammation.

By health benefits (not verified) on 25 Feb 2013 #permalink