When it comes to weight loss, something we can’t avoid is “calorie deficit”.
Energy expenditure is the total energy an individual needs to sustain life, support essential body functions, and perform daily tasks. We obtain energy from the food we eat every day.
To lose weight, an individual needs to achieve a “negative energy balance”. This is where the energy burned is more than the energy in (eat). Approximately an energy deficit of 7,700kcal is required to lose 1kg. (1)
One can achieve this in 2 ways - less input, or more output. And, these 2 ways can be extended to various modes (think low-fat diet, keto diet, intermittent fasting, and many more)
Now, let’s play a fun experiment.
Ms Jenny’s total energy requirement is 2,500 kcal. (This is the energy level for Jenny to maintain her weight, not lose and not gain). She wants to lose 4kg before her wedding, and have a more toned body figure. In order to lose 4 kg in a month, she needs to deduct 1,000 kcal per day, which means she has a 1,500 kcal quota.
There are 4 approaches for her.
Approach 1 - She can achieve 1,500 kcal through only diet planning - she eats nutritious food that keeps her full, and controls her intake.
Approach 2 - She knows she can eat what she wants as long as it does not exceed 1,500 kcal. She eats fast food and energy-dense food, but in small portions, so it won’t exceed the quota.
Approach 3 - She eats regularly, but compensates for the extra calories by jogging.
Approach 4 - She eats regularly, and does strength training exercises.
Are those 1,500 kcal really the same? Which approach is most suitable for her?
First of all, if the statement of “negative balance of 7,700 kcal loses 1kg” holds true, Ms Jenny is most probably able to lose weight with any modes above. However, the quality of these 1,500 kcal is different.
A study was done to examine how diet alone(D), exercise alone(E) and a combination of both interventions(D+E) helped in weight loss. This study consisted of 439 overweight to obese postmenopausal sedentary women.
After 12 months, participants in the diet + intervention group show the greatest improvement in every aspect. The D+E group lose 8.9 kg on average, followed by the diet-alone group (7.2kg), and the last is the exercise-alone group, in which the participants lose 2.0kg on average. The same goes for BMI, waist circumference and % of body fat loss, the D+E group shows excellent results. (2)
Other similar studies obtain the same results, proving that a combination of exercise and diet is the best way to lose weight and improve other health markers.(3), (4)
Let’s back to Ms Jenny’s case,
(ps: We didn’t discuss the exercise alone group which didn’t control the calorie intake, because we are focusing on 1,500 kcal here!)
Jenny can lose weight through diet alone. However, she can’t enjoy the extra benefit of exercise like building muscle mass, increasing metabolic rate, sleeping better and improving mental health.
Jenny can probably lose weight too, but it can’t last long. Highly processed food is usually energy dense, in order to control it at 1,500 kcal, she can only keep a small portion. Besides, these foods cause addiction and tend to make her want to eat more, eventually crashing her diet.(5) The low-quality diet might also lead her to an unhealthy condition called “skinny fat”.
Not only able to lose weight faster, but Jenny can also gain other benefits from this approach. She will become happier and more energetic, improving her sleep quality and more resistance to chronic disease.
This is the “most effort put” approach, definitely, Jenny will get the best reward by following this. She not only can achieve weight loss, and have the benefit of doing aerobic exercise, (forgot to show it in picture), she even gains muscle mass and obtains a toned body figure.
So, clearly, the winner is -- Approach 4.
However, this is just an idealistic assumption. First of all, maintaining a 1,500 kcal diet every single day for 12 months is not just difficult, but arguably impossible. (unless you’re eating the same food every day, but that’s nearly impossible too).
Secondly, it is hard to estimate how much you burnt in your workout too. (Trust me when I said the calorie showing on your smartwatch and treadmill is not as accurate as you thought).
Last but not least, the human body is complicated. We are not like robots or machines that can be measured precisely. We have emotions and hormones that will affect the way of our body works.
So what I suggest is to start from where you at. (forget about Jenny, now we are focusing on you! )
If you are a person who basically eats fast food every day, your daily meals contain pizza, a double cheeseburger set, fries and coke, then approach 2 is even more suitable for you. This is because a drastically big change is usually suffering and could not sustain.
You can start by ordering a la carte instead of a set, a cheeseburger instead of double cheese, and so on, By just reducing the portion or frequency of these foods, you can significantly start losing weight and improving your health. You don’t even have to eat sourdough and go jogging yet! (Think of the energy deficit principle)
After you adapted to it, then slowly incorporate greens into your diet.
However, if you are a person whose diet is not so extreme, you enjoy KFC and McDonald's only 3 to 4 times per month, then you can skip the step above and jump into the greens part.
Most importantly, you know why you start, understand your current situation, set your goal, and start it slowly and steadily.
(ps: unless you’re like Jenny who desperately wants to lose weight in 1 month to look good in her wedding gown. Then only you can consider a more “extreme” approach to achieve it, but only for a short term).
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