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The #1 Food That’s Making You Sick (and Fat)
Dr. Robert Lustig, author of Metabolical, explains the sugar/chronic disease connection and what you can do about it
Our food choices are making us sick, according to Robert H. Lustig, MD, Emeritus Professor of Pediatrics in the Division of Endocrinology and a member of the Institute for Health Policy Studies at University of California, San Francisco. Nearly half of all Americans suffer from at least one chronic illness, like heart disease or arthritis, and the United States ranks among the worst of all the developed countries in several of the most deadly chronic diseases: No. 1 in diabetes, No. 2 in Alzheimer’s, and No. 5 in cancer. All of these conditions — along with autoimmune disease and psychiatric illness — are on the rise, notes Dr. Lustig. And all, he says, are exacerbated by processed food.
“Processed food kills people (eventually),” Dr. Lustig writes in Metabolical: The Lure and the Lies of Processed Food, Nutrition, and Modern Medicine. He explains that sugar — the ingredient in processed food that keeps us coming back for more — acts as a driving force behind many of these disease processes, causing inflammation, feeding cancer, and altering cell function in the body and brain.
Here, Dr. Lustig shares with CoveyClub how eliminating sugar and processed food can prevent — and even reverse — the diseases we typically associate with aging, and he makes a strong case for sticking to “real food.”
CoveyClub: In Metabolical, you refer to processed food as a “consumable poison.” Can you explain why?
Dr. Lustig: If you go to the dictionary, the definition of food is: “substrate that contributes to either the growth or burning of an organism.” So, let’s take ultra-processed food. Does it contribute to burning? It turns out that every cell burns glucose for energy; the mitochondria are the little energy-burning factories inside each of these cells. Glucose activates the mitochondria in your cells to increase the rate of burning. But fructose, that sweet molecule in sugar that is laced through all ultra-processed food (specifically to get you to eat it because it activates the reward system in our brain just like heroin or cocaine and is addictive) inhibits three separate enzymes that are necessary for the mitochondria to do their job. So fructose is basically inhibiting burning, not promoting it. And my colleague Dr. Efrat Mosonego-Ornan at Hebrew University-Jerusalem has shown in a study that processed food actually inhibits growth and causes stunting. So, in fact, ultra-processed food, in part because of its high sugar content, inhibits both growth and burning and therefore is not food. In fact, it’s poison.
CoveyClub: Can you explain what sugar does to the body, and why it’s so addictive?
Dr. Lustig: Sugar is toxic in three ways. The first is that excess sugar is turned into fat in the liver. DNL — or De Novo Lipogenesis — is new fat-making. Glucose does not do that, fructose does. When the mitochondria in your liver are overwhelmed by energy (calories, i.e. from sugar), it has no choice but to take the excess energy that it can’t process and convert it into liver fat in an attempt to export it out of the liver, which will raise your serum triglycerides. A substrate for obesity or heart disease, you want to keep those down. Sugar makes them go up. That’s assuming that you have the ability to export the triglycerides out of your liver. Some people can’t get the fat out of their liver, and then you have non-alcoholic fatty liver disease and that’s worse. It will cause type 2 diabetes and all the other chronic diseases. That’s problem number one.
Problem number two: the Maillard reaction. This is the browning reaction, the same reaction that we see when we barbeque ribs on our grill. It’s why bananas brown with time. Glucose or fructose bind to proteins and when they bind to proteins they give you that brown color, the caramelization. This is the aging reaction: this reaction is the reason for wrinkles, the reason for cataracts, for brown spots on your skin, etc. You can’t stop that reaction, that is part of life, but the goal is to slow it down, not to speed it up. And it just so happens, sugar speeds it up. Fructose engages in that reaction seven times faster than glucose. That’s why sugar is worse than starch — not that starch is good — because glucose can do that reaction too, but fructose does it 10 times faster.
The third thing: the effect on the reward system of the brain. Fructose is addictive, glucose is not. Any chemical or behavior that stimulates the reward system in the brain in the extreme is addictive. So cocaine, heroin, nicotine, and alcohol all activate that area. Fructose activates it too, causing a dopamine rise, which is the reward, the motivation. But that’s just the beginning — if you keep it going — of tolerance, where you need more and more to get less and less. And then at a certain point you end up with so little dopamine being released that you end up with addiction. Imaging studies show that fructose does exactly the same thing as alcohol in the brain, and that both alcohol and sugar cause the same problems in cells in terms of the damage they do.
CoveyClub: You describe in the book how the chronic diseases that we typically associate with aging — heart disease, cancer, diabetes, Alzheimer’s — are all associated with metabolic syndrome. What is metabolic syndrome, and why is it so dangerous?
Dr. Lustig: Metabolic syndrome is routinely thought of as being a cluster of diseases that have no cure. They are all diseases of energy metabolism. So type 2 diabetes, hypertension, cardiovascular disease, dementia, polycystic ovarian syndrome (PCO) — they cluster together. It turns out that each of those diseases is just the disease of the mitochondria of that organ. When you have disease of the mitochondria of your brain you have Alzheimer’s, when you have disease of the mitochondria of the pancreas, you have type 2 diabetes, when you have disease of the mitochondria of your ovary, you have PCO, etc.
The mitochondria burn food to make ATP, which is the chemical energy that your cells need in order to carry out their functions. Mitochondria are essential and need to be at their peak capacity. When your mitochondria go south — and ultra-processed food is one of the things that makes them do so — they don’t function properly.
CoveyClub: What the medical establishment doesn’t want you to know, you say, is that their drugs can’t treat chronic disease; they only treat the symptoms. Can you explain what you mean when you say that the pathologies underlying all chronic diseases are not druggable, but foodable?
Dr. Lustig: The mitochondria are the basis for all of these chronic diseases, and while we can treat the symptoms of any given organ — for instance, statins for high LDL, insulin and oral hypoglycemics for high glucose, antihypertensives for high blood pressure — those medications are treating the symptoms of the problem, they are not treating the mitochondria. The mitochondrial dysfunction is still there. The point is that none of these diseases — these mitochondrial dysfunctions — have a treatment, because none of these medicines get to the mitochondria. Only food gets to the mitochondria. These diseases are foodable, not druggable. That’s why even treating all these diseases does not extend lifespan.
CoveyClub: Why are forces working against the medical community acknowledging the limits of the medications we use to treat chronic illness and the “whys” of metabolic disease?
Dr. Lustig: Big pharma (which funds much of the research into these diseases and their “treatments”) — tells us that these medications work. And doctors don’t want to say “I don’t know.” In medical school, you are taught two things: Prescriptions and Procedures. You’re not taught the third P, which is Prevention. Only 28 percent of medical schools have a nutrition curriculum and those who do have only 19.6 contact hours out of 6,000 devoted to nutrition. That seems kind of lopsided, since food fixes medical problems. We need doctors who understand what’s going wrong, rather than just reading a lab slip and telling you that you need a statin.
CoveyClub: As you note in Metabolical, “what your doctor doesn’t know can kill you.” How can women take control of their health? What diagnostic tests should women over 40 be getting to screen for chronic disease risk?
Dr. Lustig: The test I think is the most important is the one that the American Diabetes Association says not to draw: a fasting insulin level. I think it should be part of every standard chem panel. The reason that the ADA says don’t draw it is two-fold and they’re both wrong. The first reason is they say fasting insulin is run on multiple platforms and those platforms are not standardized. I say, so what? If it’s high, it doesn’t matter how they’re measuring it. They also say fasting insulin levels do not correlate with obesity. They are correct. But they correlate with metabolic health and that’s what is important. There are plenty of obese people who are metabolically healthy and plenty of not-obese people who are metabolically ill. And fasting insulin is a way to figure out if a normal-weight person is metabolically ill. Most doctors do fasting glucose instead. But fasting glucose is a late changer — if it’s high, the horse is already out of the barn. You want to catch the changes early in the process to prevent the problem. So a fasting insulin test is most important.
The next is uric acid, which is a proxy for sugar consumption. It’s an inhibitor of several enzymes that keep you metabolically healthy. When your uric acid goes up, that’s a sign of metabolic disturbance.
Another one that’s valuable is the ALT test, a liver function test that you can get on a standard chem panel (same with uric acid). ALT tells you whether you are storing liver fat. There are three fat depots: subcutaneous — or big butt — fat (does this bathing suit make me look fat? fat), big belly or visceral fat (which collects around the abdominal organs), and liver fat. The big butt fat turns out to be metabolically protective. That’s where the body wants to put extra energy for storage because it’s not dangerous. It may be cosmetically undesirable, but it’s not dangerous. Conversely, the big belly fat is very metabolically dangerous. (When you lose weight, you lose it from your waistline first, because you are losing the visceral fat which is more metabolically dangerous.) The liver fat is the most dangerous, because it leads to liver dysfunction.
When you overwhelm your liver with sugar, in the same way as when you overwhelm it with alcohol, the liver has no choice but to take the excess and turn it into fat to get rid of it. And some of that fat won’t make it out, so it will form fat droplets right there in the liver and then you have fatty liver disease — your liver cells don’t work right and you have insulin resistance, which makes the pancreas make more insulin to make the liver do its job. It is that excess insulin that is driving the pathological process, which is why that fasting insulin is also so valuable so you can monitor that insulin before you have diabetes.
ALT and uric acid are covered by insurance. The fasting insulin should be, but unless your doctor orders it, it’s not.
CoveyClub: While the nutrition labels reveal what’s in the food we eat, you insist that it’s what’s been done to the food that matters. What has been done to the food that threatens our health most?
Dr. Lustig: 74 percent of items in the American grocery store have been spiked with added sugar, which is toxic and addictive. They will tell you if they added sugar. But they also take the fiber out of the food and they will never tell you if they take the fiber out. The antidote to sugar is the fiber it came with.
If you consume fructose with the inherent fiber that comes in a piece of fruit, for example, that fiber — both the insoluble fiber that forms a latticework on the inside of your intestine, and the soluble fiber which plugs the holes in that lattice — forms a secondary barrier that keeps the fructose in the intestine and doesn’t let it migrate into the bloodstream (a condition known as leaky gut). The fiber keeps it from being absorbed and the microbiome chews it up for its own purposes. That’s why whole fruit works even though it contains fructose. As soon as you juice it, you’ve destroyed the fiber and now the sugar is unopposed and will get absorbed immediately, create a high fructose sugar level in the bloodstream, and go to the liver. Now you’ve got a problem. The food industry wants you to drink the juice, not eat the fruit, because you can freeze the juice. You can’t freeze an orange. They want to get rid of the fiber for shelf life — that’s what makes food storable and turns it into a commodity.
CoveyClub: Let’s talk bread. As you explain in Metabolical, wheat germ — which contains most of the nutrients provided by bread — is removed during the processing of bread. Is this why even whole grain bread (or whole grain pasta) is not the healthy choice we think it is?
Dr. Lustig: The problem is that at the USDA there is no definition of whole grain. As far as the USDA is concerned, if you start with whole grain, you can call it whole grain. But the minute you mash it up it ain’t whole anymore, is it? The other question is did they remove the germ? If it’s truly whole grain, the germ is still there. But we don’t know when it is because the USDA does not define it.
Here’s how I tell people to think about it: The fiber — or husk — of a wheatberry is 25-0 percent the weight of that wheatberry. That means the carbohydrate to fiber ratio of true whole grain bread should be about 75 percent over 25 percent (or 3:1). If the carbohydrate to fiber ratio of the bread is 3, or 4, or 5:1, then perhaps it really is whole grain bread. But that’s rare. Usually, the carb to fiber ratio of bread they call whole grain is 8:1. The only way to get there is that they took something out, so it ain’t whole.
CoveyClub: Throughout Metabolical, you repeat the mantra: “1) Protect the liver, 2) feed the gut.” What’s the best way to do this?
Dr. Lustig: Avoid ultra-processed food — and eat real food. Real food is food that came out of the ground or animals that ate the food that came out of the ground. Real food does not have a label. Real food does not need a label, because nothing was done to it. The minute the food industry does something to the food, then it needs a label. Are there labels on limes? No. Are there labels on broccoli? No. Is there a label on applesauce? Sure. Why? Is it just apples? No. The minute you did something to it, now you need a label.
CoveyClub: What is the single biggest change an individual can make in their diet to see immediate results?
Dr. Lustig: Get rid of sugar — that’s the easiest thing to do. Not easy, because sugar is hiding in everything. In fact, ultra-processed foods now account for 57% of the added sugar in our diets. It’s difficult to navigate away from. But if you do, you will see results within two weeks. In terms of metabolic health, you’ll see fasting insulin go down, triglycerides go down, your lipids go down — you might see weight loss too, though weight loss is more complex than just sugar. Eliminating sugar can possibly even reverse disease processes like type 2 diabetes and atherosclerosis and get you off your medications. Hopefully — not guaranteed. But you will definitely be healthier.
CoveyClub: Speaking of medications, you write in Metabolical about statins being over-prescribed. How does a woman know if she really needs them?
Dr. Lustig: You can use statins to lower your LDL, and people do. But the bottom line is that LDL is not the problem, it’s a symptom of the problem. There are two reasons to use a statin: One is called primary prevention and the other is secondary. Primary means your LDL is high, so you take a statin so you won’t get a heart attack. Secondary prevention is you’ve already had a heart attack, so you take a statin to prevent a second heart attack. For secondary prevention, statins are very effective. If you’re already had a heart attack, you’ve already declared yourself, it’s told you your high LDL is causing damage.
For primary prevention — which is what the pharma industry, medical community, and US Preventive Services Task Force is concerned about — they tell you to take statin for high LDL to keep you from getting a heart attack in the first place. But after 44 meta-analyses and millions of patients, do you know what the increase in lifespan is from taking a statin? Four days. I’m not against statins; they are probably the reason I’m still here. If you have familial hypercholesterolemia like I do, then it’s worth taking it. What I’m saying is that 4 out of 5 people who are prescribed statins don’t need them; 1 in 5 does. The question is how do you know which one you are? If your LDL is over 300 but your TG (triglycerides) levels are normal, you probably have familial hypercholesterolemia and you might be in the statin group. If both are elevated in the 150-250 range, you are likely insulin resistant and don’t need statins, but might do better with sugar reduction or with metformin.
CoveyClub: What can regular citizens do to fight the sugar industrial complex‘s grip on our food supply — and protect their health?
Dr. Lustig: Don’t buy bad food. And call your congressman. And teach your friends and family and doctor.
The public, unfortunately, is being misled by misinformation from the food and pharma industries. You need to take charge of your own health. We are told that a calorie is a calorie, that we should eat less, exercise more. These things don’t work. They haven’t worked, and they’re not going to work. It’s not the calories that matter, it’s the insulin that matters. Don’t eat the things that make it go up: refined carbs and sugar. As far as I’m concerned, that’s where you start.