The Body Fat Setpoint

One pound of human fat contains about 3,500 calories. That represents roughly 40 slices of toast. So if you were to eat one extra slice of toast every day, you would gain just under a pound of fat per month. Conversely, if you were to eat one fewer slice per day, you'd lose a pound a month. Right? Not quite.How is it that most peoples' body fat mass stays relatively stable over long periods of time, when an imbalance of as little as 5% of calories...

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Rabbits on a High-Saturated Fat Diet Without Added Cholesterol

I just saw another study that supports my previous post Animal Models of Atherosclerosis: LDL. The hypothesis is that in the absence of excessive added dietary cholesterol, saturated fat does not influence LDL or atherosclerosis in animal models, relative to other fats (although omega-6 polyunsaturated oils do lower LDL in some animal models). This appears to be consistent with what we see in humans.In this study, they fed four groups of rabbits...

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What's the Ideal Fasting Insulin Level?

Insulin is an important hormone. Its canonical function is to signal cells to absorb glucose from the bloodstream, but it has many other effects. Chronically elevated insulin is a marker of metabolic dysfunction, and typically accompanies high fat mass, poor glucose tolerance (prediabetes) and blood lipid abnormalities. Measuring insulin first thing in the morning, before eating a meal, reflects fasting insulin. High fasting insulin is a marker of metabolic problems and may contribute to some of them as well.Elevated fasting insulin is a hallmark...

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The Dirty Little Secret of the Diet-Heart Hypothesis

The diet-heart hypothesis is the idea that saturated fat, and in some versions cholesterol, raises blood cholesterol and contributes to the risk of having a heart attack. To test this hypothesis, scientists have been studying the relationship between saturated fat consumption and heart attack risk for more than half a century. To judge by the grave pronouncements of our most visible experts, you would think these studies had found an association between the two. It turns out, they haven't.The fact is, the vast majority of high-quality observational...

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Butyric Acid: an Ancient Controller of Metabolism, Inflammation and Stress Resistance

An Interesting FindingSusceptible strains of rodents fed high-fat diets overeat, gain fat and become profoundly insulin resistant. Dr. Jianping Ye's group recently published a paper showing that the harmful metabolic effects of a high-fat diet (lard and soybean oil) on mice can be prevented, and even reversed, using a short-chain saturated fatty acid called butyric acid (hereafter, butyrate). Here's a graph of the percent body fat over time of...

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Malocclusion: Disease of Civilization, Part IX

A SummaryFor those who didn't want to wade through the entire nerd safari, I offer a simple summary.Our ancestors had straight teeth, and their wisdom teeth came in without any problem. The same continues to be true of a few non-industrial cultures today, but it's becoming rare. Wild animals also rarely suffer from orthodontic problems.Today, the majority of people in the US and other affluent nations have some type of malocclusion, whether it's...

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Malocclusion: Disease of Civilization, Part VIII

Three Case Studies in OcclusionIn this post, I'll review three cultures with different degrees of malocclusion over time, and try to explain how the factors I've discussed may have played a role.The Xavante of Simoes LopesIn 1966, Dr. Jerry D. Niswander published a paper titled "The Oral Status of the Xavantes of Simoes Lopes", describing the dental health and occlusion of 166 Brazilian hunter-gatherers from the Xavante tribe (free full text). This tribe was living predominantly according to tradition, although they had begun trading with the...

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Malocclusion: Disease of Civilization, Part VII

Jaw Development During AdolescenceBeginning at about age 11, the skull undergoes a growth spurt. This corresponds roughly with the growth spurt in the rest of the body, with the precise timing depending on gender and other factors. Growth continues until about age 17, when the last skull sutures cease growing and slowly fuse. One of these sutures runs along the center of the maxillary arch (the arch in the upper jaw), and contributes to the widening...

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Malocclusion: Disease of Civilization, Part VI

Early Postnatal Face and Jaw DevelopmentThe face and jaws change more from birth to age four than at any other period of development after birth. At birth, infants have no teeth and their skull bones have not yet fused, allowing rapid growth. This period has a strong influence on the development of the jaws and face. The majority of malocclusions are established by the end this stage of development. Birth is the point at which the infant begins...

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Malocclusion: Disease of Civilization, Part V

Prenatal Development of the Face and JawsThe structures of the face and jaws take shape during the first trimester of pregnancy. The 5th to 11th weeks of pregnancy are particularly crucial for occlusion, because this is when the jaws, nasal septum and other cranial structures form. The nasal septum is the piece of cartilage that forms the structure of the nose and separates the two air passages as they enter the nostrils. Maternal Nutritional Status Affects Fetal Development Abnormal nutrient status can lead to several types of birth defects....

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Omega-3 Eggs

Eggs are an exceptionally nutritious food, as are all foods destined to nourish a growing animal. However, one concern lies in eggs' high concentration of arachidonic acid (AA), a long-chain omega-6 fat that is the precursor to many eicosanoids. Omega-6 derived eicosanoids are essential molecules that are involved in healing, development and defense. Some of them are inflammatory mediators that can contribute to disease when present in excess. Eggs are one of the main sources of AA in the modern diet.The percent long-chain omega-6 fats (including...

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Impressions of Hawai'i

I recently went to Hawai'i for the American Society of Human Genetics meeting in Waikiki, followed by a one-week vacation on Kaua'i with friends. It was my first time in Hawai'i and I really enjoyed it. The Hawai'ians I encountered were kind and generous people.Early European explorers remarked on the beauty, strength, good nature and exellent physical development of the native Hawai'ians. The traditional Hawai'ian diet consisted mostly of taro root,...

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Heart Attack Risk Reduction: The Low-Hanging Fruit

Dr. Yongsoon Park and colleagues recently published a great article in the British Journal of Nutrition titled "Erythrocyte fatty acid profiles can predict acute non-fatal myocardial infarction". Stated simply, the title says that the fat in your red blood cell membranes, which reflects dietary fat composition, can predict your likelihood of having a heart attack*. More accurately than standard measures of heart attack risk such as blood cholesterol. Let's cut to the data. The investigators examined the fat composition of red blood cells in...

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