December 18, 2023 • 3hr 24min

Dr. Robert Lustig: How Sugar & Processed Foods Impact Your Health

Huberman Lab

In this episode, Dr. Andrew Huberman interviews Dr. Robert Lustig, an endocrinologist and expert on nutrition, sugar, and metabolic health. They discuss how different types of calories and macronutrients are processed in the body, with a particular focus on the detrimental effects of sugar and fructose. Dr. Lustig explains how the food industry has altered the food supply to make products more addictive, leading to widespread obesity and chronic disease. He provides insights on how to make healthier food choices and improve metabolic health.

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Key Takeaways

A calorie eaten is not necessarily a calorie absorbed by the body. Factors like fiber content affect how many calories are actually utilized.
Fructose is particularly problematic for metabolic health. It inhibits key enzymes for mitochondrial function and is processed differently than glucose.
Ultra-processed foods (Nova class 4) are associated with chronic metabolic diseases. Aim to get 90-93% of calories from minimally processed whole foods.
Insulin resistance and chronically elevated insulin levels drive obesity and metabolic dysfunction by blocking leptin signaling in the brain.
Artificial sweeteners can still trigger an insulin response and may increase hunger/cravings, despite having zero calories.
Reducing sugar intake is the single most important dietary change for improving health. Aim for less than 4g added sugar per serving.
Fiber is critical for gut health and blunting the negative effects of sugar/carbs. Both soluble and insoluble fiber are important.
GLP-1 agonist drugs like Ozempic can cause significant weight loss but have concerning side effects and may cause muscle loss.
The food industry intentionally adds sugar and other ingredients to make foods hyper-palatable and addictive.

Introduction

In this episode, Dr. Andrew Huberman interviews Dr. Robert Lustig, an endocrinologist and expert on nutrition, sugar, and metabolic health. They discuss how different types of calories and macronutrients are processed in the body, with a particular focus on the detrimental effects of sugar and fructose. Dr. Lustig explains how the food industry has altered the food supply to make products more addictive, leading to widespread obesity and chronic disease. He provides insights on how to make healthier food choices and improve metabolic health.

Topics Discussed

Calories and Macronutrients (6:41)

Dr. Lustig explains that while a "calorie burned is a calorie burned", a "calorie eaten is not a calorie eaten". Factors like fiber content affect how many calories are actually absorbed and utilized by the body. For example:

160 calories of almonds = only about 130 calories absorbed due to fiber content
Protein has a higher thermic effect, meaning more calories are burned in processing it
Different types of fats (omega-3s vs trans fats) have very different health effects despite same calorie content

"It's not what you do one day that kills you. It's what you do every day that kills you. If you eat ultra-processed food, high in sugar for 10 years in a row, it's going to show up in your comorbidities…ultimately it will kill you." - Dr. Robert Lustig

Glucose vs Fructose (18:23)

Dr. Lustig explains the key differences in how glucose and fructose are metabolized:

Glucose can be used by all cells for energy
Fructose is processed almost entirely by the liver
Fructose inhibits 3 key enzymes for mitochondrial function
Fructose is highly lipogenic (fat-producing) in the liver
Fructose does not suppress ghrelin (hunger hormone) like glucose does
Fructose consumption has increased 25-fold in the last century

Fruit is generally okay due to fiber content, but fruit juice and added sugars are problematic.

Insulin and Leptin Resistance (37:04)

Dr. Lustig explains how chronically elevated insulin levels drive obesity and metabolic dysfunction:

Insulin is a storage hormone that promotes fat storage
High insulin blocks leptin signaling in the brain
This causes the brain to think the body is starving, even when overweight
Leads to increased hunger and decreased energy expenditure

"Insulin is not the diabetes hormone, insulin is the storage hormone." - Dr. Robert Lustig

Ultra-Processed Foods (1:04:13)

Dr. Lustig discusses the NOVA food classification system:

NOVA 1: Unprocessed whole foods (fruits, vegetables, meat, eggs)
NOVA 2: Minimally processed foods
NOVA 3: Processed foods (canned goods, cheese, bread)
NOVA 4: Ultra-processed foods (soft drinks, packaged snacks, reconstituted meat products)

NOVA 4 foods are associated with obesity, diabetes, and other chronic diseases. Dr. Lustig recommends getting no more than 7-10% of calories from NOVA 4.

Artificial Sweeteners (2:26:40)

Dr. Lustig explains that artificial sweeteners can still trigger an insulin response, despite having zero calories:

Sweet taste on the tongue signals the brain to release insulin
Can lead to increased hunger and cravings
May result in weight gain over time
Better than sugar, but worse than water

GLP-1 Agonists (Ozempic, Wegovy) (2:45:18)

Dr. Lustig discusses the pros and cons of new weight loss drugs:

Can cause significant weight loss (16% on average)
Work by slowing gastric emptying and reducing appetite
Cause loss of both fat and muscle mass
Potential side effects: nausea, vomiting, pancreatitis, gastroparesis
Very expensive ($1300/month)
May be appropriate for some patients, but not a universal solution

Sugar Addiction (3:03:31)

Dr. Lustig explains how sugar can be addictive:

Fructose activates the reward center of the brain like drugs of abuse
Leads to dopamine receptor downregulation over time
Results in tolerance and dependence
Food industry intentionally adds sugar to make products more addictive

Recommendations for Improving Health (3:15:55)

Dr. Lustig's top recommendations:

Get rid of sugar - aim for less than 4g added sugar per serving
Go for a walk - increase physical activity
Eat more fiber - both soluble and insoluble
Choose minimally processed whole foods (NOVA 1-3)
Read food labels carefully and be aware of hidden sugars

Conclusion

This wide-ranging discussion provides a comprehensive overview of how different foods impact metabolic health, with a particular focus on the detrimental effects of sugar and ultra-processed foods. Dr. Lustig explains the biochemistry of why a "calorie is not a calorie" and how the food industry has altered the food supply to make products more addictive, leading to widespread obesity and chronic disease. He emphasizes the importance of reducing sugar intake, increasing fiber consumption, and choosing minimally processed whole foods for optimal health. While new weight loss drugs show promise, Dr. Lustig cautions that they are not a universal solution and come with concerning side effects. Overall, this episode provides listeners with a deeper understanding of nutrition science and actionable advice for improving metabolic health.