Why Calories Don't Count

1. Calorie Counts Are Misleading, Not Meaningless

ALL of the calorie-counts that you see everywhere today are WRONG.

Caloric availability. The calorie counts on food labels are estimates of the total energy in the food, not the amount your body can actually extract and use. This is because digestion and metabolism are complex processes that vary depending on the food's composition and how it's processed. The number of calories listed on a package is not the same as the number of usable calories we finally get out of the food.

Three calorie values. There are three different calorie values to consider:

• A – the number of calories actually in the food
• B – the number of calories on the side of the pack
• C – the number of usable calories we finally get out of the food

Understanding the difference. While calorie counts aren't perfect, they're still a useful starting point for making informed food choices. The key is to understand that they're just estimates and that the actual number of calories your body absorbs can vary.

2. The Atwater Factors: A Century-Old Approximation

We live not upon what we eat, but upon what we digest.

Atwater's contribution. Wilbur Olin Atwater developed a system for estimating the usable energy in food based on its protein, fat, and carbohydrate content. These "Atwater factors" (4 calories per gram of protein and carbs, 9 calories per gram of fat) are still widely used today.

Limitations of Atwater factors. The Atwater system is a simplification of a complex process. It doesn't account for factors like:

• The digestibility of different foods
• The thermic effect of food (the energy your body uses to digest and process food)
• Individual differences in metabolism

Specific factor system. A more precise, but less practical, approach is to use specific factors for different foods. For example, the energy value of protein in rice is different from the energy value of protein in potatoes.

3. Digestion: The Food-to-ATP Tube

Deliveroo’s outlook is simple: the way to eat healthy is by having more information and more selection.

From food to fuel. Digestion is the process of breaking down food into smaller molecules that your body can absorb. This process involves both mechanical and chemical digestion, starting in the mouth and continuing through the stomach and small intestine.

Key organs and enzymes:

• Salivary amylase: Breaks down starch in the mouth
• Pepsin: Digests protein in the stomach
• Bile: Emulsifies fats in the small intestine
• Pancreatic enzymes: Further break down carbs, fats, and proteins

Small intestine absorption. The small intestine is where most nutrients are absorbed into the bloodstream. The large intestine absorbs water and electrolytes, forming feces.

4. ATP: The Universal Energy Currency

I like keeping my metabolism on its toes. Like what’s it gonna be today, complete starvation or 6,000 calories?

ATP is key. Adenosine triphosphate (ATP) is the primary energy currency of cells. The metabolism of glucose, fatty acids, and amino acids is all about generating ATP.

Mitochondria power plants. Mitochondria are organelles within cells that are responsible for producing most of the ATP. They use the Krebs cycle and oxidative phosphorylation to convert food into energy.

Metabolic pathways:

• Glycolysis: Breaks down glucose into pyruvate
• Beta-oxidation: Breaks down fatty acids into acetyl-CoA
• Krebs cycle: Oxidizes acetyl-CoA to produce electrons
• Oxidative phosphorylation: Uses electrons to generate ATP

5. Protein: The Satiety Powerhouse

When life gives you lemons, ask for something higher in protein

Protein's unique role. Protein is more satiating than carbs or fat, meaning it helps you feel fuller for longer. This is due to a combination of factors, including:

• Increased release of satiety hormones
• Slower digestion
• Higher thermic effect

Protein leverage hypothesis. The body prioritizes protein intake, so if a diet is low in protein, you'll eat more overall to meet your protein needs.

High-protein diets. High-protein diets can be effective for weight loss, but it's important to choose healthy protein sources, such as lean meats, fish, beans, and lentils.

6. Fiber: The Gut's Best Friend

My internet connection and my diet are missing one thing in common… Fibre

Two types of fiber. Dietary fiber is a type of carbohydrate that the body can't digest. There are two types of fiber:

• Soluble fiber: Dissolves in water and forms a gel, slowing digestion
• Insoluble fiber: Adds bulk to stool and promotes regularity

Burkitt's fiber hypothesis. Denis Burkitt proposed that a lack of fiber in the Western diet was a major cause of many chronic diseases.

Benefits of fiber:

• Promotes healthy bowel function
• Reduces the risk of colon cancer
• Helps regulate blood sugar levels
• May lower cholesterol levels
• Promotes satiety

7. Ultra-Processed Foods: A Modern Dilemma

This cannot be a piecemeal, voluntary approach – calorie labelling should be mandatory for all restaurants, cafes and takeaways, with no exemptions, to create a level playing field and ensure people are able to make informed choices about the food they eat, wherever they choose to eat.

NOVA classification. Carlos Monteiro developed the NOVA system for classifying foods based on their degree of processing. Ultra-processed foods are industrial formulations with many ingredients, often including additives not used in home cooking.

Characteristics of ultra-processed foods:

• High in sugar, salt, and fat
• Low in protein and fiber
• Often contain artificial flavors, colors, and preservatives
• Highly palatable and addictive

Health concerns. Diets high in ultra-processed foods are linked to weight gain, obesity, type 2 diabetes, and other chronic diseases. This is due to a combination of factors, including their high caloric density, low satiety, and impact on gut health.

8. Privilege Shapes Calorie Choices

The cheapest food is that which furnishes the largest amount of nutriment at the least cost; and the best food is that which is both most healthful and cheapest.

Socioeconomic disparities. Access to healthy food is not equal. Low-income communities often have limited access to fresh produce and an abundance of fast-food restaurants and convenience stores selling ultra-processed foods.

Food insecurity. Food insecurity, or limited access to food due to lack of money or resources, is a major problem in many wealthy countries. This can lead to both undernutrition and overconsumption of unhealthy foods.

The role of privilege. Money, time, and knowledge all play a role in shaping food choices. Those with more resources are better able to afford and prepare healthy meals.

9. Focus on Food Quality, Not Just Quantity

We live not upon what we eat, but upon what we digest.

Beyond calorie counting. Instead of obsessing over calorie numbers, focus on the quality of your food. Choose whole, unprocessed foods that are rich in nutrients and fiber.

Prioritize protein and fiber. These two nutrients are key for satiety and can help you eat less overall. Include protein sources like lean meats, fish, beans, and lentils in your diet. Load up on fiber-rich foods like fruits, vegetables, and whole grains.

Limit sugar and refined carbs. These foods are often high in calories and low in nutrients. They can also cause rapid spikes in blood sugar, leading to cravings and overeating.

Last updated: April 1, 2025