I'll try and keep this as simple as possible
To lose weight, you can't escape the simple law of thermodynamics. You aren't a special snowflake. You don't have a slow metabolism. You don't have an issue with your thyroid and if you did, you'd get it treated by your doctor.
Throughout the day, our body burns energy, in the form of calories. It's impossible to work out how much calories you burn exactly each day, but there are calculators online that can give you a rough estimate.
There are several factors at play that determine how much calories our body burns. They are;
If someone is heavy, their body has to burn more energy to move all that weight around, correct?
The taller someone is, they genetically have to fill out more space, which in turn makes them naturally heavier. This is a reason you often see tall lanky people and short fat people. Shorter people take up less space, making their body burn less energy.
Gender - males genetically carry around more muscle mass than females do. Males in most cases are going to burn more energy than a female.
Activity level - someone who has a physical job is going to burn more energy than someone who has a desk job
Muscle mass - the more muscle mass you have on your body, the more energy your body burns. A 6'2" 200lb guy @ 10% body fat would burn more energy than a 6'2" guy @ 30% body fat.
Now, you've worked out your maintenance levels, or Total Daily Energy Expenditure (TDEE) using an online calculator. What next?
Well, you eat. It's my firm belief that diet will consist of 80% of your desired results. The rest coming from exercise.
What do you eat? Truth be told, you can eat whatever you want, providing you eat less than your TDEE.
This means you're going to have to count calories(!). This seems arduous and mind-numbing at first, but the more you do it, the more of a habit it will become. There are sites online where you can track what you've eaten, there are apps on your phone, too. Hell, I kick it old school and still use a pad and pencil.
One of the most important things you can buy is a digital food scale. You can pick up a decent one for $10. Weigh out all your food. Read the nutritional tables on the back of food packets CORRECTLY. Don't eat the whole bag of chips when it says they're 450 calories. That 450 calories is probably a 50g SERVING when the whole packet is probably 200g, which is going to total 1800 calories. So read correctly and measure correctly!
Now, when I say, eat whatever you want, theoretically, it's true, but be smart about food choices. Sure, you can put gas in the car and it'll run, but 10 years down the road the engines gonna be shit. You put premium in, it's gonna be good. Just ... be smart about food choices
Now - the QUALITY of your weight loss is going to be determined by your MACRONUTRIENT intake and your workout regime.
There are 3 macronutrients that make up the total amount of calories in foods. They are;
1g of fat is equal to 9 calories
1g of protein and carbs is equal to 4 calories
Try it yourself. This 500mL can of Mother energy drink has 228 calories. It's an energy drink, there's going to be no fat or protein in it. Sure enough, on the back it says one serve 500mL - 57g of sugar. 57x4 = 228 calories
Now, fat and protein are ESSENTIAL macronutrients - the lack of either of them in your diet causes negative effects on your body.
Lack of fat causes poor hormone production which could make you feeling irritable, angry, short tempered, even depressed
Lack of protein in your diet can cause muscle loss
Carbohydrates are non-essential. Our body can survive just fine without them.
Now how much protein and fat should we be consuming? Honestly, there are a lot of formulas out there to follow, some of them blowing things out of proportion. I feel, protein consumption should be between 0.8g - 1.5g per pound of lean body mass (how much you'd weigh if you didn't have any fat on you. 160lb guy at 10% body fat would have 144lb of LBM)
Fat consumption should be around .45g per pound of bodyweight.
Now for someone who is 5'10", 220lb male @ 30% body fat with a moderate activity level, their maintenance levels could be around 3000 calories a day.
They'd have 154lb of LBM. They should be consuming anywhere from 123g to 231g of protein a day. Their fat consumption should be around 99g
If they had 150g of protein a day and 100g of fat a day, their total calorie consumption would bring them to 1500 calories. That's a calorie deficit of 1500 calories. How big a deficit you choose is up to you, as long as you're hitting your MINIMUM FAT and PROTEIN requirements and stimulating your muscles, you will RETAIN AS MUCH MUSCLE AS POSSIBLE. DO NOT WORRY ABOUT LOSING MUSCLE. This is the number one problem a lot of people say when they restrict calories too much. If you are sure you lost muscle on your diet then you either didn't consume enough protein, didn't stimulate your muscles, or a combination of both, OR, you didn't have as much muscle to begin with in the first place.
Now, diet has been covered.
Your body has to have a reason to hold onto it's muscle, right? Feeding it protein is a good start, however, if you're not stimulating your muscles, then your going to find that your body is going to be chewing away at your muscles for energy, and that's not good, right?
If you're reading this, it's a good chance you haven't been in a gym before or done anything with weight training. Bicep curls do not count as weight training.
You're a beginner, your best bet is to hop on a 3 day a week full-body routine. No, I don't mean hitting 2 or 3 muscle groups a day, working your way around the body for the rest of the week. I mean, you're doing movements, compound movements to be precise, that work a lot of muscles, to help build your STRENGTH.
It is entirely possible to gain muscle and lose fat as a beginner - these are noob gains - they don't last long. However, it is entirely possible to gain STRENGTH while on a diet. Strength is your Central Nervous System (CNS) recruiting muscles to move the weight. The heavier the weight, the more CNS recruitment is happening to move the weight.
This is why an advanced lifter, who can squat 400lb raw, can probably do it only once a week. It taxes their CNS to the extreme. A beginner, maybe starting off with an empty bar, could potentially get away with doing it every day of the week. But for simplistic sake, we'll stick to a program like Starting Strength that goes for 3 days a week, on non-consecutive days.
Now, the lifts in the program are the squat, deadlift, bench, overhead press and press clean*
*I highly recommend swapping these out for a row. Press cleans to a beginner are a highly technical lift and the tradition SS program is negligent of the upper back.
His rep ranges are only 5 per set. 3 working sets.
Now before you go, "Oh, no weight lifting, I don't wanna get big and gross like arnie" ...
Uh, please! It takes years ... decades even, before you get a physique like Arnie.
Weight lifting is the fountain of youth.
The SS program is workout A - squat, bench, deadlift
Workout B - squat, OHP, row
This is the original template - I would recommend adding pullups, assisted or non-assisted at the end of workout B, alternating between overhand and underhand.
Sorry I wrote this in a rush, and if anyone decides to read it and ask questions I'll try and get round to answering them all. Peace out.