WEIGHT LOSS EXPERT: Calories Are a LIE! The Real Reason You Can't Lose Weight Will Shock You

Why Calories Don’t Tell the Whole Story

Giles begins by addressing the common misconception that weight loss is simply a matter of calories in versus calories out. While acknowledging the physics behind calories, he explains that not all calories are created equal. The body’s ability to extract and use calories depends heavily on the type and quality of food consumed. For example, protein requires more energy to digest and metabolize, meaning that for every 100 calories of protein eaten, the body only effectively uses about 70 calories. In contrast, fats are nearly 100% available as energy, and carbohydrates vary depending on fiber content. Fiber-rich foods, primarily from plants, require more effort from the body to extract calories, which can reduce the net calories absorbed.

Giles highlights that calorie counting, a strategy popularized in the early 1900s by Lulu Hunt Peters, was initially a useful tool when obesity was less prevalent and diets were more balanced. However, today’s obsession with calorie numbers often ignores the nutritional quality of food. People may reduce calories but consume highly processed, nutrient-poor foods, which undermines health and sustainable weight loss.

The Role of Food Processing and Preparation

The discussion moves to how food processing affects calorie availability. Cooking and processing make calories more accessible to the body. For instance, raw meat requires more energy to digest than cooked meat, and processed forms like stews or lasagna allow the body to extract more calories from the same amount of food. Similarly, drying or grinding foods like corn increases calorie availability compared to eating them whole.

This explains why fast food and ultra-processed foods, which are often cheaper and more convenient, contribute to weight gain. They provide easily accessible calories with less effort from the body, often lacking fiber and essential nutrients. Giles points out that in places like the UK and the US, a significant portion of calories consumed comes from these ultra-processed foods, which are engineered for taste and convenience rather than health.

Quality Over Quantity: What Does Healthy Eating Really Mean?

Giles stresses that while quantity matters to some extent, the quality of the diet is far more important. Healthy eating is not a one-size-fits-all concept; it depends on individual factors such as age, ethnicity, activity level, and health status. For example, an Olympic athlete’s nutritional needs differ vastly from those of an elderly person in a hospital bed.

He also explains that obesity became a widespread concern around the mid-1980s, coinciding with the rise of fast food chains and increased availability of processed foods. The convenience and affordability of these foods have made unhealthy eating patterns more common, contributing to the obesity epidemic.

Genetics and Individual Differences in Weight Management

One of the most eye-opening parts of the conversation is the role genetics play in body weight and metabolism. Giles explains that genetics can influence how much people eat, how efficiently they metabolize food, and where fat is stored in the body. This explains why two people eating the same diet can have very different body compositions and health outcomes.

He uses the analogy of running speed to illustrate genetic limitations: just as not everyone can be an Olympic sprinter, not everyone has the same genetic predisposition for weight management. However, genetics are not destiny. Behavioral changes and lifestyle adjustments can still lead to significant improvements in health and weight, even for those genetically predisposed to obesity.

Ethnic differences also matter. For example, South Asians tend to gain weight more easily around the abdomen and have a higher risk of metabolic diseases at lower body mass indexes compared to other populations. This highlights the need for more nuanced approaches to weight and health that consider genetic and cultural factors.

Practical Dietary Advice: Focus on Protein, Fiber, and Sugar

When asked what people should focus on changing in their diets, Giles recommends three key nutritional targets: adequate protein intake (about 16% of daily energy), significantly increasing fiber consumption (doubling current averages), and limiting free sugars to less than 5% of daily energy. These targets can be adapted to different cultural diets and food preferences but provide a universal framework for healthier eating.

He emphasizes that increasing fiber, which comes from fruits and vegetables, is crucial for health and weight management. Free sugars—those detached from fiber such as in fruit juices, honey, and processed sweets—should be minimized because they contribute to excess calorie intake without nutritional benefits.

Reading Food Labels and Avoiding Marketing Traps

Giles also discusses the confusion caused by food marketing and labeling. Many products are packaged to appear healthy, using green colors or buzzwords like “high protein,” even when they are still processed and calorie-dense. For example, protein-enriched tortilla chips may sound healthy but remain a processed snack with limited nutritional value.

He advises consumers to focus on three key label components: protein, fiber, and sugar content. Avoid obsessing over calories alone, as this can be misleading. Instead, consider the overall nutritional quality of the food and how it fits into your weekly diet.

The Brain’s Role in Weight Loss Resistance

A particularly striking insight is why losing weight is so difficult: the brain actively resists weight loss. Evolutionarily, the brain perceives weight loss as a threat to survival and triggers mechanisms to restore lost weight. This includes increasing hunger and lowering metabolism, making sustained weight loss a biological challenge.

Giles explains that after losing weight, a person’s metabolism slows down, meaning they must eat less than someone of the same weight who was never heavier to maintain their new weight. This biological resistance explains why many diets fail in the long term and why weight regain is common.

The Importance of Muscle Mass and Exercise

Maintaining muscle mass is critical for metabolic health, especially as people age. Contrary to popular belief, metabolism per unit of muscle remains stable until around the mid-60s. The problem is that many people become less active and lose muscle mass as they age, which contributes to weight gain and health decline.

Exercise, particularly strength training, helps preserve muscle mass and can temporarily boost metabolism, aiding in weight maintenance. While exercise alone is not highly effective for weight loss, it is essential for long-term health and preventing weight regain.

The Role and Risks of Weight Loss Drugs

The conversation also touches on the rise of weight loss drugs like Ozempic, which have gained popularity for their effectiveness in reducing appetite and promoting weight loss. Giles supports their use for people with severe obesity or related health conditions but warns against their cosmetic use by individuals who do not medically need them.

He cautions that these drugs do not improve diet quality or behavior; they simply reduce hunger. Misuse can lead to malnutrition or excessive weight loss, especially in those who are already lean. Therefore, careful medical supervision and appropriate patient selection are crucial.

Final Thoughts: Changing the Food Environment and Mindset

Giles concludes by advocating for systemic changes to make healthy food more affordable and accessible. Currently, unhealthy foods are often cheaper and more convenient, which disproportionately affects lower-income populations and exacerbates health inequalities.

He encourages people to focus on behavioral changes such as controlling their food environment—keeping unhealthy snacks out of the house—and planning for cravings with healthier alternatives. Understanding one’s eating habits and triggers is key to managing weight effectively.