Good Calories, Bad Calories

1. The conventional wisdom on diet and health is based on flawed science

"If sciences are based on supposition and opinion…the object is to command assent, not to master the thing itself."

Flawed foundations: The dietary guidelines that have shaped public health policy for decades are built on shaky scientific ground. The diet-heart hypothesis, which proposes that dietary fat causes heart disease, gained traction despite inconsistent evidence. Ancel Keys, the hypothesis's main proponent, selectively chose data that supported his theory while ignoring contradictory findings.

Oversimplification and bias: The nutrition research community often oversimplified complex issues, leading to misinterpretations and erroneous conclusions. This was compounded by confirmation bias, where researchers tended to see what they expected to see, rather than objectively evaluating all available evidence. The result was a self-reinforcing cycle of flawed studies and misguided public health recommendations.

2. Dietary fat was wrongly vilified, while refined carbohydrates were overlooked

"To attribute obesity to 'overeating,' as the Harvard nutritionist Jean Mayer suggested back in 1968, 'is as meaningful as to account for alcoholism by ascribing it to 'overdrinking.'"

Fat phobia: The demonization of dietary fat, particularly saturated fat, led to widespread adoption of low-fat diets. This shift was based more on correlation than causation, and ignored the potential benefits of certain fats in the diet. The American Heart Association and other influential organizations promoted low-fat diets without sufficient evidence of their long-term safety or efficacy.

Carbohydrate blindspot: While fat was vilified, the potential negative effects of refined carbohydrates and sugar were largely ignored. This oversight may have contributed to the rise in obesity and related chronic diseases, as people replaced fat in their diets with these easily digestible carbohydrates.

3. The rise of obesity and chronic diseases coincides with low-fat diet recommendations

"The circumstances militated against any acquisition of new dietetic habits."

Unintended consequences: As low-fat diet recommendations became widespread, rates of obesity and related chronic diseases began to increase. This paradoxical outcome suggests that the conventional wisdom on nutrition may have been misguided.

Nutritional transition: The shift towards low-fat, high-carbohydrate diets coincided with:

• Increased consumption of refined grains and sugars
• Development of processed low-fat foods high in added sugars
• Decreased consumption of whole foods and natural fats

These changes may have contributed to metabolic disturbances and weight gain in populations following the new dietary guidelines.

4. Insulin plays a crucial role in weight regulation and chronic disease development

"Insulin (in a test tube) will monopolize the attention of the insulin-degrading enzyme (IDE), which normally degrades and clears both amyloid proteins and insulin from around the neurons."

Insulin's multifaceted role: Insulin is not just a blood sugar regulator; it's a master hormone that influences:

• Fat storage and mobilization
• Appetite regulation
• Cellular energy metabolism
• Inflammation and oxidative stress

Chronic hyperinsulinemia: Consistently elevated insulin levels, often caused by diets high in refined carbohydrates, may contribute to:

• Insulin resistance
• Obesity
• Type 2 diabetes
• Cardiovascular disease
• Potentially even neurodegenerative diseases like Alzheimer's

Understanding insulin's central role in metabolism challenges the simplistic "calories in, calories out" model of weight regulation and disease development.

5. The carbohydrate hypothesis offers a better explanation for obesity and related diseases

"The carbohydrate hypothesis rests upon two simple propositions."

Alternative framework: The carbohydrate hypothesis proposes that refined carbohydrates and sugars, rather than dietary fat, are the primary drivers of obesity and related chronic diseases. This hypothesis better explains the observed patterns of disease in populations transitioning to Western diets.

Key principles:

1. If a disease becomes more common with diabetes or metabolic syndrome, insulin and blood sugar likely play a role
2. If insulin and blood sugar are involved, refined carbohydrates in the diet may be a contributing factor

This framework provides a more comprehensive explanation for the diseases of civilization and offers potential avenues for prevention and treatment.

6. The thrifty gene theory fails to explain the obesity epidemic

"Species adapt to their environment over successive generations. Those that don't, die off. When food is abundant, species multiply; they don't get obese and diabetic."

Flawed assumptions: The thrifty gene theory proposes that humans evolved to efficiently store fat during times of plenty to survive periods of famine. However, this theory:

• Lacks strong evolutionary evidence
• Doesn't explain why obesity affects some populations more than others
• Fails to account for the rapid rise in obesity rates over recent decades

Alternative explanations: Rather than a genetic predisposition to store fat, the obesity epidemic may be better explained by:

• Changes in dietary composition, particularly increased refined carbohydrate consumption
• Hormonal and metabolic disruptions caused by modern processed foods
• Environmental factors that influence appetite and metabolism

7. Exercise alone is not an effective solution for weight loss

"For a long period the role of exercise in weight control was disregarded, if not actually ridiculed."

Limited impact: While exercise has numerous health benefits, its effectiveness for weight loss is often overstated. Research shows that:

• The calories burned through exercise are easily offset by small increases in food intake
• Increased physical activity often leads to increased appetite
• The body tends to compensate for increased energy expenditure by reducing metabolism

Complex relationship: The association between physical activity and weight is not straightforward:

• Obesity may lead to decreased activity, rather than the other way around
• Both obesity and inactivity may be symptoms of the same underlying metabolic disturbances
• Poverty is associated with higher obesity rates, despite often involving more physical labor

8. Hunger and metabolism adapt to defend against weight loss

"Keys's conscientious objectors reduced their total energy expenditure by over half in response to a diet that gave them only half as many calories as they would have preferred."

Metabolic adaptation: When calorie intake is restricted, the body responds by:

• Reducing basal metabolic rate
• Decreasing non-exercise activity thermogenesis
• Increasing hunger and food-seeking behaviors

Persistent effects: These adaptations can persist long after the period of calorie restriction, making it difficult to maintain weight loss. This explains why:

• Most dieters regain lost weight
• Successive dieting attempts often become less effective
• Maintaining a reduced weight requires ongoing calorie restriction or significant lifestyle changes

9. Sugar and refined carbohydrates may be the primary culprits in chronic diseases

"Fructose is significantly more reactive in the bloodstream than glucose, and perhaps ten times more effective than glucose at inducing the cross-linking of proteins that leads to the cellular junk of advanced glycation end-products."

Unique metabolic effects: Sugar, particularly fructose, has distinct metabolic effects that may contribute to chronic disease:

• Rapid absorption and metabolism in the liver
• Increased production of triglycerides and uric acid
• Greater potential for glycation and oxidative stress

Hidden dangers: The widespread addition of sugar and refined carbohydrates to processed foods may be driving the rise in chronic diseases:

• Increased insulin resistance and hyperinsulinemia
• Promotion of inflammation and oxidative stress
• Disruption of normal appetite regulation

10. The diseases of civilization emerge with the introduction of Western diets

"As incomes rise and populations become more urban, diets high in complex carbohydrates give way to more varied diets with a higher proportion of fats, saturated fats and sugars."

Consistent pattern: Across diverse populations, the introduction of Western dietary patterns is associated with increased rates of:

• Obesity
• Type 2 diabetes
• Cardiovascular disease
• Certain cancers
• Dental caries and other chronic conditions

Key dietary changes:

• Increased consumption of refined grains, sugar, and processed foods
• Decreased intake of whole, unprocessed foods
• Shift from traditional, varied diets to more homogeneous, energy-dense diets

This consistent pattern suggests that the Western diet, rather than genetic factors or total calorie intake, may be the primary driver of these chronic diseases.

Last updated: January 23, 2025