Fat Loss

What to Eat to Lose Weight and Body Fat

Calorie counting only gets you so far. Protein intake and food quality decide whether a fat-loss and energy deficits actually sticks.

Energy balance is real, but oversimplified. Measuring it is riddled with several errors, which makes weight loss and fat loss harder than the "maths" suggests.
Protein is probably the most underrated fat-burning nutrient. It helps with fat loss and maintaining a healthy body weight in 4 different ways.
Food quality and nutrient density are also underrated. Protein and fibre-rich low-energy-density foods are what you should fill your diet with.

"Calories in, calories out." It's the fundamental equation determining "energy balance," which governs your body weight. Or is it? The physics behind the energy balance equation is solid, but the application of it is not as straightforward — and even if you get the maths right, what those calories are made of changes how easy or hard the whole weight loss process feels.

Energy balance: The maths

At its core, body weight change follows the first law of thermodynamics: "energy cannot be created or destroyed, only transferred or transformed". When energy intake exceeds energy expenditure, the excess is stored, primarily as fat tissue. But when expenditure exceeds intake, stored energy is mobilised to meet the deficit — mainly from fat, but also from carbohydrate and protein stores in the liver and muscles¹.

Energy intake and expenditure are usually measured in "calories," which are actually kilocalories (1,000 calories = 1 kilocalorie). Your body (like everything else) follows the laws of physics, making energy balance the ultimate determinant of successful fat loss. However, the apparent simplicity of this equation masks a lot of complexity in both measuring it and adjusting its individual parts to "create" a calorie deficit. In our opinion, you're better off focusing on doing things that lead to a negative energy balance, rather than obsessing over energy balance itself.

Calories in: Why tracking is harder than it looks

Energy intake is easy to measure, but difficult to measure correctly. You can have the most detailed, sophisticated tracking system in the world, and it still won't measure what your body is actually absorbing. Food-logging studies generally show underreporting of energy intake by 10–20%, though some people underreport by 40% or more². This comes down to:

Misjudging portion sizes.
Failing to account for calorie-dense additions (cooking oils, spreads, condiments).
Different cooking or processing methods.
Selective counting (ignoring weekends or eating out) and relying on flawed food databases.
Restaurant and pre-packaged food labels are notoriously inaccurate, and liquid calories (e.g., milk, alcohol, sodas, and sauces) are frequently overlooked entirely.

Add up all these errors, and you're really left asking: how good is your educated guess? Trying to get it to the nearest 100 calories — no chance.

Calories out: Your total daily energy expenditure

The other side of the equation is your total daily energy expenditure, and it has four components:

Basal Metabolic Rate: The energy required for your basic biological needs. Accounts for roughly 60–75% of your energy expenditure for most people.
Thermic Effect of Food: The energy required to digest, absorb, and use the energy you've eaten — usually 8–12% of energy expenditure.
Exercise Activity Thermogenesis: all planned exercise. Typically, 5–15% of energy expenditure, but can exceed 50% for very active people and drop under 5% for inactive ones.
Non-Exercise Activity Thermogenesis: all other movement that isn't sleeping, eating, or exercising — fidgeting, posture, incidental activity. It varies enormously between people (think farmworker versus desk worker) and is a crucial, often-overlooked component of energy balance³.

All four components fluctuate day to day and hour to hour, which makes assumptions about how much energy they use genuinely difficult. Exercise is relatively easy to track — minutes, sessions, distance. But when you reduce how much you're eating, your body also reduces how much it expends. This is called "metabolic adaptation" or "adaptive thermogenesis."

Your basal metabolic rate drops as your organs become more energy-efficient, and you subconsciously reduce your non-exercise energy expenditure too, resting more and moving less. These compensatory behaviours can add up to hundreds of calories a day⁴. Your body isn't trying to sabotage your diet; these are evolutionary survival mechanisms that kept us alive through famines.