- Weight loss and gain are due to either consuming too much or too little energy, regardless of the source.
- If you consume exactly as much as you need, you won’t gain or lose any weight unless you’re very unhealthy
- When you spend a long time consuming less than you need, your body adapts
- Personal Trainers use different tactics at this point to ensure weight loss continues whilst maintaining muscle
Think back to high school physics: you were taught about the laws of energy that state the energy put into a system has to be equal to the which leaves it. Systems in school examples usually had electric power as the input. This created a variety of energy outputs; light, heat, sound, kinetic or stored potential energy (ie, power stored in another battery).
If this system is our body, then the input is food. Food contains calories – which is a unit of energy – and provides us with the fuel to create energy output. Most of this gets used up in moving around and generating chemical processes in our complex body, then comes thermoregulation (ie, keeping our body at the right temperature relative to our surroundings), making noise and, lastly, if you’re sufficiently spiritual, emitting light.
However if the food we consume exceeds our expenditure in all of these forms, we need to store it. Luckily our body has a clever, in-built storage system, to make sure none of our consumed energy is wasted and can be kept for a later instance when we may not have access to food. Fat.
Yep, that’s basically what fat cells (or adipose tissue, if you’re being a smart-arse) are for. They keep extra energy stored, and when we don’t consume enough to satisfy our output requirements it is mobilised.
That is the simple truth of the matter, regardless of what trendy workouts and diets one does. Yes, the type of foods and workouts can contribute to whether weight lost or gained is in the form of fat or muscle, but that’s for another article. Essentially, workouts only add to your kinetic energy usage or increase the chemical energy needed to repair and grow muscles.
So, how do you get started?
Firstly, you'd need to know how many calories you get through just by existing. There are online calculators that should give you a vague indication using your age, height and weight. Logic says that the bigger you are, the more calories you burn lugging yourself around.
Say your daily BMR (Basal Metabolic Rate) is 1500 calories. This doesn’t include exercise, nor does it take into account how active your lifestyle is in general. You could take this up to 1800-2000 with a workout, or drop it closer to 1200 by sitting on the sofa all day.
Your intake should end up being anywhere from 15-30% less than your required maintenance calories. Again, we won’t go into the difference between consuming these calories through fast food and cocktails, but if you consume these calories in even a relatively healthy way you’ll lose weight. People have even shown it done on a pure-sugar diet (a doctor did it on twinkies!) just to prove how consistent the theory is but it can result in one getting quite sick from a lack of nutrition and hamper progress.
You can often lose weight much more quickly at first. If you’re currently overweight it’s likely to be the result of prolonged overconsumption. Your body knows that calories are abundant and it needn’t be stingy with them. You have a high burn rate so a deficit is easy to achieve. Over time though, this will drop and your body will begin to be more conservative, increasing its efficiency.
Our evolution only really involved 4 ways of dying. Illness, succumbing to predators, falling off a cliff, and starvation. Fear helped keep us away from cliffs and lions, and our appetite helped us steer clear of starvation. When we start losing weight in calorie deficit, it kicks in to ensure we don’t “die”.
There are two options when your initial weight loss stagnates.
You need to be quite careful with both options. If you overdo the first option, it can result in your body resorting to muscle breakdown for energy. This is not ideal for optimising one’s body composition because with reduced muscle-mass comes reduced calorie-usage. Think of each muscle fibre as a creator of kinetic energy – the more you have, the more they all burn - and this will drop your maintenance calories even further, making a deficit harder to maintain in the long run. Additionally, the goal is rarely to have less muscle.
You also can’t keep dropping calories forever. Your stress and sex hormones and energy systems go bananas and start resorting to all sorts of complicated, unhealthy measures to stop you from “dying”. You also tend to become incredibly lazy to subconsciously conserve energy.
It’s very hard to manage the second option well. For most people, after a period of several weeks in a deficit, the temptation to overindulge and go back into consuming a surplus is irresistible. Their body is not only burning fewer calories than before, but it is desperate to return to its weight of “safety”. They also forget to keep monitoring their intake out of sheer relief, and their bodies pile on fat in even the slightest surplus to get them back to what their body feels is a “normal” weight.
Many also underestimate how long it takes to get their body to reverse metabolic adaptation. It’s part of why the foundations behind cheat meals are sketchy – they are based on encouraging this it takes a matter of weeks not hours to fix.
A good personal trainer specialising in weight loss understands these mechanics well. They've studied the experiments working out the optimal percentages and time periods to work with on each cycle. More important though, is that they have experience with personal training clients who have been through such journeys. Calorie calculators aren’t 100% individualised and none of the numbers is set in stone; from the percentage deficit one should be in, to the length of time one should have between diet breaks. Every client is individual, and good PTs monitor mood, sleep, performance and other factors to gauge what steps to take with a client.
The whole process requires constant adjustments to ensure a client is able to not only see consistent progress but also to maintain adherence to their deficit over enough time to see results. It’s not an easy process, as it’s something that our bodies were only meant to experience in times of famine. However, it is one that should be far less traumatising than famine and much more productive, with correct management.