Why All Calories Are Not Created Equal: The Science of Food Source and Metabolism

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• The Calorie Myth Debunked
• The Fiber and Absorption Effect
• The High Energy Cost of Protein
• Good Fats vs. Bad Fats
• Fructose vs. Glucose: A Critical Difference
• The Direct Link Between Sugar and Diabetes
• Full Transcript

The Calorie Myth Debunked

Dr. Robert Lustig, MD, a neuroendocrinologist, begins by making a crucial distinction that is central to understanding nutrition. He states that while a calorie burned is always a calorie burned, a calorie eaten is not just a calorie eaten. The source of those calories matters immensely for metabolic health. This foundational concept debunks the outdated and oversimplified advice that weight management is solely about "calories in versus calories out." Dr. Robert Lustig, MD, emphasizes that where calories come from determines where they go in the body and what diseases they may cause.

The Fiber and Absorption Effect

Dr. Robert Lustig, MD, uses a powerful example with almonds to illustrate how fiber alters calorie absorption. When you consume 160 calories worth of almonds, you do not absorb all 160 calories. The fiber in the almonds forms a gel-like barrier in the intestines, which prevents the full absorption of fats and carbohydrates. As Dr. Robert Lustig, MD, explains, only about 130 of those 160 calories actually enter your bloodstream. The remaining calories continue down the digestive tract to feed the gut's microbiome, which consists of 100 trillion bacteria. This process demonstrates that the net energy yield from food is not determined by its label calorie count but by its composition.

The High Energy Cost of Protein

The metabolic processing of protein requires a significant energy investment from the body, a concept known as the thermic effect of food. Dr. Robert Lustig, MD, clarifies that to metabolize protein for energy, the body must first remove amino groups from the protein molecules. This biochemical process demands energy. In fact, digesting protein requires approximately twice the amount of energy compared to digesting carbohydrates. Therefore, while protein and carbohydrates may contain the same number of calories per gram on a label, the net energy your body gains from protein is lower because it expends more energy to break it down.

Good Fats vs. Bad Fats

Dr. Robert Lustig, MD, presents a stark contrast between healthy and harmful fats, both of which contain 9 calories per gram. On one side are omega-3 fatty acids found in wild fish and flax seeds. These fats have proven anti-inflammatory properties and support heart and brain health. On the opposite end are artificial trans fats. Dr. Lustig describes trans fats as a "consumable poison" because neither human enzymes nor gut bacteria can properly digest them. This indigestibility is why the food industry uses them to extend shelf life, but it also causes them to line arteries and the liver, directly contributing to chronic disease. This comparison proves that calorie source is a primary determinant of health outcome.

Fructose vs. Glucose: A Critical Difference

Dr. Robert Lustig, MD, highlights the most critical comparison: fructose versus glucose. Glucose is the fundamental energy currency of life; every cell in the body can metabolize it, and the body tightly regulates blood glucose levels. Fructose, however, is metabolized almost exclusively in the liver. Dr. Robert Lustig, MD, states a crucial fact: "Not a single biochemical reaction in the body requires dietary fructose." When consumed in excess, as it is in modern diets high in sugar, the liver has no choice but to convert this fructose into liver fat. This liver fat accumulation is a primary driver of insulin resistance and metabolic disease, setting the stage for diabetes.

The Direct Link Between Sugar and Diabetes

Dr. Robert Lustig, MD, concludes with unequivocal data on the toxicity of sugar. The pathway is clear: excess fructose consumption leads to liver fat production, which causes insulin resistance. To overcome this resistance, the pancreas is forced to secrete increasingly larger amounts of insulin. Eventually, the pancreas becomes exhausted and can no longer produce enough insulin, resulting in type 2 diabetes. Dr. Lustig is adamant, stating there are "no ifs, ands, or buts"—sugar causes diabetes. This direct causal relationship underscores the critical importance of understanding that a calorie from sugar is not the same as a calorie from other sources and has profound implications for public health education and dietary choices.

Full Transcript

Dr. Anton Titov, MD: Is a calorie a calorie? The "calorie is a calorie" myth is explained by an endocrinologist and prominent nutrition expert. Why does one calorie burned equal another calorie burned, but one calorie eaten does not equal another calorie eaten? What is the role of gut bacteria in calorie turnover in the human body? For example, almonds.

Is a calorie a calorie? The "calorie is a calorie" myth is just that. A calorie is not a calorie when it is eaten. A calorie burned is a calorie burned. The source of calories matters a lot. All calories are not the same. Debunking the calorie myth is easy if you look at where calories come from. To digest one calorie of protein, you need to burn more energy.

Is a calorie a calorie? Many ask today. The "calorie is a calorie" myth has to be broken once and for all. That is why counting calories does not matter. It is the source of calories that matters most for health. Calories from fructose create liver fat storage and lead to disease. Fructose leads to insulin increase and pancreas exhaustion. Because a calorie is not a calorie. It matters where calories come from.

Video interview with a leading expert in pediatric endocrinology and nutrition. Medical second opinion confirms that a child obesity diagnosis is correct and complete. Medical second opinion also confirms that treatment for child obesity is required.

Dr. Robert Lustig, MD: We now know that a calorie is not just a calorie. "Calorie is a calorie" is a myth. Everyone must understand that.

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Dr. Robert Lustig, MD: Many people say, "A calorie is just a calorie. The source of calories does not matter. You have to restrict calories. You have to exercise more." Is a calorie just a calorie? A calorie burned is a calorie burned. You can burn your calories when you sleep, or you can burn your calories during vigorous exercise. ATP is the molecule of chemical energy. When ATP releases its energy, it releases the same amount of energy for every molecule. It doesn't matter how we got to the ATP. But when energy is already converted to ATP, a calorie is a calorie. A calorie burned is a calorie burned.

This question is important. Is a calorie eaten a calorie eaten? Does it matter where the calories came from in terms of where they go? Does the source of calories matter?

We have really good data about this. The data clearly shows that a calorie is not a calorie. The type and source of calories are important for good nutrition. Where those calories come from determines where they go. It determines what diseases they cause in the meantime.

Dr. Anton Titov, MD: I will give you the perfect example. Let's start with almonds. You eat 160 calories in almonds. How many calories do you absorb from these almonds? You absorb 130 calories when you eat 160 calories in almonds. Where did the other 30 calories go?

Dr. Robert Lustig, MD: There is fiber in almonds. This fiber covers the inside of your intestines like a gel. This gel consists of soluble and insoluble fibers. You can see this white fiber gel on electron microscopy. This gel acts as a secondary barrier. It prevents the absorption of the carbohydrates and fats from the almonds. More of what you ate goes further down the intestine. The intestinal bacteria get the almonds.

A human consists of 10 trillion cells, but we have 100 trillion bacteria in our intestines. Each of us is really a big bag of bacteria with legs. Those bacteria have to eat something. They have to survive. What do bacteria in your intestines eat? They eat what you eat. The question is, how much food do you get versus how much food do bacteria get? When you eat almonds, the bacteria get more food because of the fiber in almonds. So, 160 calories get past your lips, but only 130 calories get to your bloodstream. Because a calorie is not a calorie. 160 calories in almonds equals just 130 calories that are absorbed into your body.

Another example: protein. You metabolize protein for energy. You then need to remove the amino group from a protein molecule. This costs energy. You have to invest energy first to get energy back from the protein. You have to invest twice the amount of energy when you digest protein compared with carbohydrate. There is less energy required to break down carbohydrates. The same number of molecules of energy is released from protein and from carbohydrate. But you need to put twice more energy in when you digest protein. Because a calorie is not a calorie.

How about fat? On one side, there are omega-3 fatty acids from wild fish and flax seeds. Fish and flax are foods that are healthy for your heart. They have anti-inflammatory and anti-dementia properties. Fish and flax will save your life. On the other side are trans fats. This will kill you. Trans fats are consumable poison. Because your body cannot digest trans fats. Your bacteria cannot digest trans fats. This is why the food industry puts trans fats into food. That food stays longer without bacteria. Trans fats in food increase shelf life. It is storage on the shop shelf. Trans fats decrease depreciation. Depreciation is an accounting term for how fast something becomes obsolete. But if your bacteria cannot digest them, trans fats line your arteries and your liver.

Both omega-3 fatty acids and trans fat are 9 calories per gram. But one will save your life and another one will kill you. Because a calorie is not a calorie.

Finally, let's discuss fructose and glucose. Glucose is the energy of life. Every cell on the planet burns glucose for energy. Glucose is so important that if you don't consume enough glucose, your body will make it. Maybe you do not consume any glucose. Then your liver will actually turn other molecules into glucose. The body will maintain your blood glucose level. This is how important glucose is for your body. The brain only consumes glucose for energy under normal physiological circumstances. Yes, unless the brain switches to ketones. This takes three to four days of continuous fasting. But under normal physiological conditions, your brain needs glucose.

But fructose is something else. Not a single biochemical reaction in the body requires dietary fructose. There is no need for dietary fructose. Fructose is not metabolized in your body. Fructose is only metabolized in the liver. There is an excess of fructose in food. Then the liver has no other choice. The liver turns fructose into liver fat. Liver fat causes all chronic metabolic diseases that we discussed today.

Glucose and fructose are also not the same, but they are both in sugar. Glucose will cause the pancreas to secrete more insulin. Just as protein-rich foods like almonds are not the same. Just as omega-3 fatty acids and trans fat are not the same. Fructose will make your liver sick. The pancreas has to make even more insulin. Ultimately, the pancreas burns out. The pancreas is exhausted by making too much insulin for too long. Then you have Type 2 diabetes.

We have data that shows categorically that sugar causes diabetes. No ifs, ands, or buts. Sugar causes diabetes.

Dr. Anton Titov, MD: I very much appreciate and applaud what you are doing. Your job is to help educate people. My job is to educate people. That is what we are doing here today.

Dr. Robert Lustig, MD: We need people to understand that they are in charge. They need to understand that they can take control of their lives if they choose to.

People have to be confident and responsible for their lives. People have to make their own decisions in life. But like in any war, you have to watch what you do. You have to watch where you step. This is a war. It is a war between our wallets and our health. When people understand that, presumably they will choose the correct side to be on. That is important to know.

Dr. Anton Titov, MD: Dr. Robert Lustig, MD, thank you very much for this very insightful and fascinating conversation. Thank you for outlining what is known in the scientific community: that sugar is highly toxic in amounts that exceed those in the natural environment. Sugar in excess is highly toxic, as is any white powder.

Dr. Robert Lustig, MD: Just like any other powder. Coca leaves are medicinal; cocaine is a drug of addiction. Opium is medicinal; heroin is a drug of addiction. Pick your white powder. This (sugar) is just the cheap one.

Dr. Anton Titov, MD: Thank you for this conversation. Thank you. Is a calorie a calorie? The "calorie is a calorie" myth. Video interview with Dr. Robert Lustig. Calories from fat, protein, sugar—are they equal in value?