Monday, November 24, 2014

The Diet Debacle

SAN FRANCISCO – Two seemingly benign nutritional maxims are at the root of all dietary evil: A calorie is a calorie, and You are what you eat. Both ideas are now so entrenched in public consciousness that they have become virtually unassailable. As a result, the food industry, aided and abetted by ostensibly well-meaning scientists and politicians, has afflicted humankind with the plague of chronic metabolic disease, which threatens to bankrupt health care worldwide.

The United States currently spends $147 billion on obesity-related health care annually. Previously, one could have argued that these were affluent countries’ diseases, but the United Nations announced last year that chronic metabolic disease (including diabetes, heart disease, cancer, and dementia) is a bigger threat to the developing world than is infectious disease, including HIV.

These two nutritional maxims give credence to the food industry’s self-serving corollaries: If a calorie is a calorie, then any food can be part of a balanced diet; and, if we are what we eat, then everyone chooses what they eat. Again, both are misleading.

If one’s weight really is a matter of personal responsibility, how can we explain toddler obesity? Indeed, the US has an obesity epidemic in six-month-olds. They don’t diet or exercise. Conversely, up to 40% of normal-weight people have chronic metabolic disease. Something else is going on.

Consider the following diets: Atkins (all fat and no carbohydrates); traditional Japanese (all carbohydrates and little fat); and Ornish (even less fat and carbohydrates with lots of fiber). All three help to maintain, and in some cases even improve, metabolic health, because the liver has to deal with only one energy source at a time.

That is how human bodies are designed to metabolize food. Our hunter ancestors ate fat, which was transported to the liver and broken down by the lipolytic pathway to deliver fatty acids to the mitochondria (the subcellular structures that burn food to create energy). On the occasion of a big kill, any excess dietary fatty acids were packaged into low-density lipoproteins and transported out of the liver to be stored in peripheral fat tissue. As a result, our forebears’ livers stayed healthy.

Meanwhile, our gatherer ancestors ate carbohydrates (polymers of glucose), which was also transported to the liver, via the glycolytic pathway, and broken down for energy. Any excess glucose stimulated the pancreas to release insulin, which transported glucose into peripheral fat tissue, and which also caused the liver to store glucose as glycogen (liver starch). So their livers also stayed healthy.

And nature did its part by supplying all naturally occurring foodstuffs with either fat or carbohydrate as the energy source, not both. Even fatty fruits – coconut, olives, avocados – are low in carbohydrate.

Our metabolisms started to malfunction when humans began consuming fat and carbohydrates at the same meal. The liver mitochondria could not keep up with the energy onslaught, and had no choice but to employ a little-used escape valve called “de novo lipogenesis” (new fat-making) to turn excess energy substrate into liver fat.

Liver fat mucks up the workings of the liver. It is the root cause of the phenomenon known as “insulin resistance” and the primary process that drives chronic metabolic disease. In other words, neither fat nor carbohydrates are problematic – until they are combined. The food industry does precisely that, mixing more of both into the Western diet for palatability and shelf life, thereby intensifying insulin resistance and chronic metabolic disease.

But there is one exception to this formulation: sugar. Sucrose and high-fructose corn syrup are comprised of one molecule of glucose (not especially sweet) and one molecule of fructose (very sweet). While glucose is metabolized by the glycolytic pathway, fructose is metabolized by the lipolytic pathway, and is not insulin-regulated. Thus, when sugar is ingested in excess, the liver mitochondria are so overwhelmed that they have no choice but to build liver fat. Today, 33% of Americans have a fatty liver, which causes chronic metabolic disease.

Prior to 1900, Americans consumed less than 30 grams of sugar per day, or about 6% of total calories. In 1977, it was 75 grams/day, and in 1994, up to 110 grams/day. Currently, adolescents average 150 grams/day (roughly 30% of total calories) – a five-fold increase in one century, and a two-fold increase in a generation. In the past 50 years, consumption of sugar has also doubled worldwide. Worse yet, other than the ephemeral pleasure that it provides, there is not a single biochemical process that requires dietary fructose; it is a vestigial nutrient, left over from the evolutionary differentiation between plants and animals.

It is therefore clear that a calorie is not a calorie. Fats, carbohydrates, fructose, and glucose are all metabolized differently in the body. Furthermore, you are what you do with what you eat.Combining fat and carbohydrate places high demands on the metabolic process. And adding sugar is particularly egregious.

Indeed, while food companies would have you believe that sugar can be part of a balanced diet, the bottom line is that they have created an unbalanced one. Of the 600,000 food items available in the US, 80% are laced with added sugar. People cannot be held responsible for what they put in their mouths when their choices have been co-opted.

And this brings us back to those obese toddlers. The fructose content of a soft drink is 5.3%. Of course, many parents might refuse to give soft drinks to their children, but the fructose content of soy formula is 5.1%, and 6% for juice.

We have a long way to go to debunk dangerous nutritional dogmas. Until we do, we will make little headway in reversing an imminent medical and economic disaster.

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    1. CommentedJoan Meyer

      I wonder if sugar is responsible for alcoholism. Why are there drinkers and heavy drinkers who go home and go to bed. Then there are alcoholics who, I believe are addicted to sugar, and therefore stay up drinking until they fall down. Also, many depressives seem to eat an amazing amount of sugar in any form. Could there be a connection?

    2. CommentedDennis Argall

      The elephant in the can is this:

      "Of the 600,000 food items available in the US..."

      This sophisticated argument about lipolysis might have usefully noted that in reality a huge proportion of that 600,000 scarcely deserve description as food. Issues of digestion, metabolism, benefit and damage relate also to the diverse additives for taste, fluffiness, and preservation.

      Margaret Thatcher (before she became Prime Minister before she became Meryl Streep) as an industrial chemist showed the ice cream manufacturers how to make more money by adding air and emulsifiers. Prominent on the list of additives to dairy items to make them fluffy and now especially pervasive in anything labelled 'lite' is caraggeenen.

      — despite this reality in medical science:

      "Carrageenan-induced inflammation in the rat paw represents a classical model of edema formation and hyperalgesia, which has been extensively used in the development of nonsteroidal anti-inflammatory drugs and selective COX1-2 inhibitors. "

      this carcinogenic inflammatory agent has approval as a food additive. Lots of other examples can be brought to the bar, as with this on-going war:

      There is need for advocacy to:
      - avoid processed foods generally; hunt for fresh, demand fresh, which demand might shift pricing of fresh more favourably (I am sure much consumption of non-fresh is because too hard, too expensive
      - get public focus on 'food miles' - the impact of centralised industries and vast distances travelled by foods increases the need for preservatives and flavour enhancers
      - work to improve the shopping and cooking skills of young people especially, not least because an increasing proportion have such limited home exposure to fresh food and cooking (recognise that the diminishment of such skills is a decline in civilisation)
      - encourage community gardens and other home food production, not just for the probably modest direct food gains but also for the healing value of the social and physical exercise and the mind and lung opening effects of living in an ecology.

    3. Commentedjames durante

      "Our hunter ancestors..." and "our gatherer ancestors..." Uhhhh, Dr. Lustig MIGHT know something about diets, but he clearly knows nothing about our ancestors. The generally accepted phrases in the anthropological literature are "gatherer-hunter" and "horticulturalist." In neither case did people eat meals of ONLY fat or ONLY carbohydrates. Our ancestors had an exquisite knowledge of the plants and animals in their land base and ate a wide variety of foods that contained protein, fats, and carbohydrates.

      True, not all calories are equal; true, excess sugar intake is terribly unhealthy. But it is also true that Americans are eating enormous numbers of calories while maintaining an almost completely sedentary lifestyle. If there is one thing that our ancestors did it was MOVE and not by car.

      I am in good health; I eat a balanced diet with little sugar. I bike (road bike and commuting), run a bit, garden a lot, and try to be positive. I'll stick with what is working. The last thing we need is people freaking out because they have a potato on their plate (when it is fat only day) or a nut on their plate (when it is carb only day).

    4. CommentedWilliam Wilson

      Thanks Dr. Lustig for an excellent article on the toxic nature of sugar. We now believe that when you add high glycemic carbohydrates to an environment of insulin resistance from consuming too much fructose, the brain takes a hit. Over time these dietary elements can trigger a chronic disease called Carbohydrate Associated Reversible Brain syndrome or CARB syndrome.

      People with CARB syndrome can develop up to 22 brain dysfunction symptoms that interfere with their ability to function. Because the brain plays a key role in auto-regulating fat stores, people with CARB syndrome start to store excessive body fat at virtually any caloric intake. At this stage they are often incorrectly diagnosed with depression, ADHD, PTSD, OCD, eating disorders, anxiety disorders, bipolar II, fibromyalgia, irritable bowel syndrome and similar conditions. Learn more at

    5. Commentedrobot 5x

      Great article on a topic with lots of important nuances. A small correction though - Atkins is not "all fat and no carbohydrate" at all; it is "high protein and low carbohydrate". Big difference.

      One only has to delve into the discussion boards at diabetic websites to see how people are recognising the benefits of a low-carb diet for better glycaemic control of diabetes (type 1 and 2). Current (ADA) recommendations for a diet of 60% carbs are totally unmanageable for those on even the most intensive insulin therapy.

      Mr Lustig could also have highlighted that the huge rise in obesity and diabetes coincides exactly with the promulgation of the "low fat-high carb" diet advice from the 70s onwards. Junk food, HFCS and lack of exercise certainly are factors - but our huge swing towards a high carbohydrate diet is the biggest cause of obesity. That includes any high carb foods you can think of - bread, pasta, rice, etc.

      It also may be a coincidence that these kind of foods are easier to package and market by corporations - just look at the breakfast cereals in a supermarket; all over-priced carbs and sugar.

      Check out Richard Bernsteins 'Diabetes Solution' - he's a diabetic MD who switched to a low-carb diet, and is now seeing the glycaemic control, HDL and Cholesterol results ever. Also recommended is Gary Taubes' NY Times Article - 'what if it's all been a big fat lie?'.

        CommentedWilliam Lagakos

        @ robot 5x,
        I think categorizing Atkins as "all fat and no carbohydrate" is pretty close to the mark; "high protein and low carbohydrate" sounds more like Dukan. But you bring up some interesting points otherwise.

    6. CommentedDiana Hinova

      Spot-on! Of course this makes sense biochemically, and anyone who has tried 'food combining' (eating carbs and proteins in separate meals with enough time in between to digest them) know that it is both a great weight-control diet and effective at easing a variety of digestive problems.

      But I have to add to the criticism toward the food industry, which is predictably solely driven by profit motive, criticism toward the US government. it's approaches with both the outmoded food pyramid, and even more so with 'MyPlate', suggest exactly that everyone should force their body to metabolize all 'food groups' at every meal. That is poor advice indeed, and does not make it clear or easy for individuals to make healthy choices. It keeps the focus on a balance between these 'food groups' rather than on the quality of foods, or their quantity (though some suggestion on serving sizes is admittedly offered). So, people are advised to balance competing foods on their plate at every meal, and it is only natural that they enjoy some more than others. It sets up an unrealistic, and unhelpful from a metabolic perspective, expectation.