Scientific Weight Loss Programme: Four Steps to Crafting Your Personalised Fat-Loss Diet Plan

Dietary Plan:
Four Steps to Tailor Your Own Fat-Loss Diet

Breaking energy equilibrium is the essence of weight gain or loss.
When we consume more energy from food than our bodies expend, excess energy is stored as glycogen in the liver and muscles. The remainder is almost entirely converted into fat, deposited throughout the body.

Therefore, as long as energy intake does not exceed expenditure, one will not gain weight regardless of daily food choices—be it chips, fried chicken, or ice cream—because the energy is utilised. Conversely, even consuming entirely healthy foods daily will lead to weight gain if intake surpasses daily expenditure.
Thus, bodily energy surplus results in fat accumulation. To burn body fat and achieve weight loss, one must create an energy deficit.

So how much of an energy deficit is required to shed half a kilogram of body fat?

Approximately 3,900 kilocalories.

Why 3,900 kcal? Wasn't it stated earlier that 1 gram of fat provides 9 kcal? Shouldn't 500 grams of fat then equate to 4,500 kcal?

Correct, if it were pure fat, it would be 4,500 kcal per 500 grams. However, adipose tissue itself contains some water, with the remainder being pure fat—roughly 80%. Therefore, 500 grams of body fat contains approximately 3,900 kcal.
Thus, when the energy deficit between intake and expenditure reaches 3900 kcal, approximately one jin of fat is shed.
How then does one create this energy deficit? First, one must ascertain daily caloric requirements. This necessitates calculating total daily energy expenditure.
As previously discussed, daily energy expenditure comprises three main components: basal metabolic rate (BMR), energy required for food digestion and absorption, and energy expended through daily physical activity.
Thus, the first step is to calculate BMR using the relatively straightforward Owen formula:
Female BMR = 7.18 × weight (kg) + 795 (in kcal)
Male BMR = 10.2 × weight (kg) + 879, also in kcal.
The second step involves multiplying the calculated BMR by an activity factor to determine total daily energy expenditure.
If you lead a sedentary lifestyle with minimal movement, your activity factor is 1.1, meaning your daily expenditure is only slightly higher than your basal metabolic rate.
If you engage in moderate-intensity exercise 1–2 times weekly, your activity factor increases to 1.2. For 3–5 weekly sessions, apply a factor of 1.3. Daily high-intensity exercise warrants a factor of 1.5.

For example: My weight is 80 kilograms. My basal metabolic rate calculated using the formula is 10.2 × 80 + 879 = 1695 kcal. I exercise 4 times weekly, so my activity factor is 1.3. Therefore, my daily energy expenditure = 1695 × 1.3 ≈ 2204 kcal.

This represents my approximate total daily energy expenditure. Note that energy required for food digestion is not factored into this calculation, as its contribution is negligible, the calculation is overly complex, and the margin of error is significant.

Now that we know our daily energy expenditure, creating an energy deficit for weight loss involves consuming fewer calories than this amount.

How do we determine the appropriate level of caloric deficit?