BMR explained: the free calories your body burns at rest
BMR is the energy your body burns just to stay alive — heart, lungs, brain, kidneys — while you lie still. It is about 60 to 70 percent of everything you burn each day, and Burnie subtracts it as the big baseline in your deficit.
Your body burns calories even when you do nothing. Lying in bed, your heart still beats. Your lungs still breathe. Your brain still thinks. That resting burn has a name: BMR, short for Basal Metabolic Rate. It is the biggest chunk of energy you spend each day — bigger than your walk, your workout, or your digestion. In Burnie, BMR is the big baseline that gets subtracted before anything else.
BMR is about 60 to 70 percent of your total burn
Scientists call it resting energy expenditure, or REE. It is the energy your body uses at complete rest, just to keep you alive. According to a verified medical reference, "Resting energy expenditure (REE) typically accounts for 60 to 70 percent of total energy expenditure." That means most of the calories you burn each day happen without you moving at all. Your heart, lungs, brain, kidneys, and liver do this work. They never switch off. So when Burnie works out your daily deficit, BMR is the biggest number on the 'burn' side.
What nudges your BMR up or down
BMR is mostly set by your size and your muscle. You cannot change it in a day. But these things move it a little, up or down:
A spicy meal or ice-cold water can really raise your BMR for weight loss.
mostly falseMostly false — explained simply. Food does give your body a small calorie burn while digesting, called the thermic effect of food (TEF). But it is only about 10 percent of your daily energy, and it is temporary. Spicy food and cold water might add a tiny flicker for an hour, but they do not change your true BMR. Your BMR is set by your size, your muscle, your age, and your height — not by a single meal. So no chilli or cold water trick will melt fat. The honest work is a steady calorie deficit.
The science of estimating BMR (general knowledge, not a Burnie claim)
Scientists have built formulas to guess BMR from simple body facts. The Harris and Benedict equation, published in 1919, uses your weight, height, and age. For men it is: BMR = 66.473 + 13.7516 x weight(kg) + 5.0033 x height(cm) - 6.755 x age. For women: BMR = 655.0955 + 9.5634 x weight(kg) + 1.8496 x height(cm) - 4.6756 x age. Later, in 1990, Mifflin and St Jeor made a newer version from 498 adults: men: REE = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5; women: REE = 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161. These are general science. Burnie estimates your BMR from your weight, height, age, and sex — the same body facts these formulas use. We do not need to name which formula Burnie picks inside the app. The point is: BMR can be estimated from simple numbers you already know.
How Burnie uses your BMR as the free baseline
The bottom line
BMR is the calories your body burns just to stay alive — about 60 to 70 percent of your whole day. It is set mostly by your size, your muscle, and your age. You cannot trick it with a spicy meal. In Burnie, it is the big free baseline subtracted in food minus (bmr + active_calories). Log your food, move a bit, and let your BMR do its quiet work every day.