To lose fat, calorie deficit is the fastest and most reliable method. Your return on investment for tweaking macro ratios is going to be minimal at best.
Weight loss and losing fat are conceptually simple, but not easy. It takes time and work. The numbers are general, not specific, but they provide a roadmap. Metabolisms differ. Muggle food and snacking will have an impact on the amount of time it takes to reach a certain goal.
The key is managing your body fat percentage. As a general rule of thumb (it’s not a strictly linear relationship between caloric output and pounds lost) it takes a 3900 calorie deficit per pound of weight lost. If you’re getting sufficient protein per day, your muscle mass will maintain itself. Carbs and fats are intertwined in our metabolisms. Excess carbs get converted and stored as fat. Excess fat also gets stored, and also gets excreted.
Generally speaking, carbs are used for on-demand energy. Proteins get broken down into essential amino acids. Fats are used to shore up deficits. What this means is that after you burn up your on-demand energy, your body kicks in and starts converting those stored fat molecules into glucose for more on-demand fuel.
Step 1: Calculate your BMR: http://www.bmi-calculator.net/bmr-calculator/
Step 2: Calculate your body fat percentage: http://www.bmi-calculator.net/body-fat-calculator/
Step 3: Pick your body fat percentage target from the above chart.
Step 4: Calculate how many pounds of fat you have. If you’re 180 pounds and have 35% body fat, that’s 63 pounds of fat.
Now you have your numbers, you can create your goal. 0% body fat (and dead) would be 117 pounds. Lets say you want to have 15% body fat. This means your target weight will be around 138 pounds. From there, you know that you need to lose 48 pounds (180-132.)
Your body has to incur a caloric deficit in order to burn off the weight. It also has to obtain enough protein to maintain muscle mass. Ketogenic diets kickstart the metabolism to more efficiently burn fats. Low carb high protein diets do the same. The amount of effort you put in, however, remains about the same. There are roughly 9 calories per gram of fat.
Using that general rule of thumb, we can say that with 48 lbs to lose, we need a 187,200 calorie deficit to achieve our weight loss goal.
I have a BMR of 2300 calories per day, roughly. 2000 calorie Soylent meals daily gives me a 300 calorie deficit. By eating just Soylent, if my BMR stays the same, then in 20 months I’ll reach my target of 132 pounds. The tricky part is that you have to increase your level of activity to maintain the same BMR. As you lose weight, you’re burning fewer calories (by carrying fewer pounds) and becoming more efficient.
20 months seems like a long time. Consider that in this scenario, simply by walking 5 miles a day, you’re increasing the caloric deficit by 300-400 calories, without a large amount of exertion or stress. This changes the time to reach your target from 20 months to 8-10 months.
Now if you go all in and ramp up to a strenuous exercise program, you can increase your muscle mass at the same time that you’re losing fat. This means that you can have a higher mount of fat relative to your total bodyweight to achieve the same percentage. To keep it simple, lets say you want to gain 10 pounds of muscle. This puts your 0% fat weight at 127 pounds. For 15% bodyfat, your target weight is 150. You’ll be consuming more protein to build muscle mass while at the same time increasing your caloric deficit to burn fat. If you ran 5 miles and did 45 minutes of free-weight lifting and stretching, your caloric deficit increases to 1000. Since you’re wanting to increase muscle mass, you’re going to increase the amount of protein you’re taking in. 300 calories of protein would be a decent middle ground (assuming you’re operating on the US RDA.)
In this mildly strenuous scenario, you’re operating on a daily 700 calorie deficit, trying to achieve 150 pounds. This gets you to your target in 6 months.
Soylent + a carefully chosen protein source = weight management dream.
If you worked out in a relaxed way, you an burn 300 calories in a day with ease. If you work out really hard, you’re looking at 700+ calories. On the flip side, consuming less calories per day is easier. Since the example above expects 2300 calories per day, with 2000 calories of Soylent, the example gets a 300 per day starter bonus deficit. Moderate exercise is psychologically easier, and results in a 600 calorie deficit, compared to a 1000 calorie deficit for strenuous workout.
If you ease into it and manage your weight, you can be fit and cut like a movie star in 8 months or less, just by walking 5 miles a day and watching what you eat. If you work out like crazy and watch what you eat, you could get there in 4-5 months. Anything sooner I would be afraid of health consequences (this would be for an almost obese male at 180 pounds.) If you’re 10 pounds overweight, you could have a Brad Pitt physique in less than 60 days.
I was actually shocked to find out that women actually have it easier. They can have a higher body fat percentage and achieve a better physique with fewer calories burned.