I was having a conversation with a client the other day and it dawned on me: I skipped over the basics of 'how weight-loss works'. We all start our journeys in different places, some with more knowledge then others, and some with the desire to lose weight, but no direction or starting point for understanding how diet and exercise work to reduce weight, which can make the process a little easier to stick to. So I took some time, dug into the way, way back machine and thought about the basics that I didn't know when I started. Here, I've come up with a short list of building-block basics to help demystify weight-loss:
1. The amount of calories in a pound of body fat.
For starters, it's critical to understand how many calories are in a pound of body fat. This is fundamental to understanding why cutting calories results in weight-loss and eating more calories than you need results in weight gain.
One pound of body fat roughly equates to 3500 calories.
Hang onto this, it's important for the next part.
2. Understanding calorie maintenance, calorie surplus and calorie deficit.
Calories in versus calories out: it's the rule for weight-loss. In order to gain weight you must consume more calories than your body uses in a day and to lose weight you must consume less calories than your body uses in a day.
Calorie maintenance is when you consume the amount of calories your body needs in a day. Since your body has a use for all of those calories, you can expect to have no weight-gain. Since you have not eaten below your maintenance, your body will have no need to reach into the reserve (body fat) for energy and you can expect to have no weight-loss either.
A calorie surplus is when you eat more calories than your body needs. Put another way: you are eating above your calorie maintenance. Since your body doesn't have a way to use the extra calories, it will store those excess calories to use later as adipose tissue (commonly know as body fat).
A calorie deficit is when you eat less calories than your body needs so you are eating below your calorie maintenance. In order to keep your body humming along, it will dip into the reserved energy (body fat) and use it to keep running. This is how you lose weight.
3. How this works with weight gain and weight loss:
Eating in a surplus leads to weight gain. Whether that's 100 calories or 500 calories, you'll gain weight by consuming more calories than your body needs.
For example, let's say your body needs 1800 calories a day to function. This is known as your maintenance calories.
If you eat in a surplus for one week, meaning you eat above that 1800 calories, those extra calories can be stored a body fat. Since one pound of body fat equates to 3500 calories, if you eat an additional 500 calories a day above maintenance for 7 days, you would expect to gain 1 pound of body fat in a week. Meaning, if you ate 2300 calories a day for 7 days, you could expect to gain 1 pound of body fat by the end of the week.
1800 (Maintenance Calories) x 7 (days) = 12,600 (weekly calorie maintenance)
+ 500 (Surplus Calories) x 7 (days) = 3,500 (additional calories/week)
2,300 (calories per day) x 7 (days) = 16,100 (Weekly calories) or a surplus of 3500 calories for the week.
On the other hand, if you ate below your calorie maintenance and consumed 1300 calories a day, 500 calories below your maintenance of 1800, you could expect to lose 1 pound of weight by the end of the week.
1800 (Maintenance Calories) x 7 (days) = 12,600 (weekly calorie maintenance)
- 500 (Calories) x 7 (days) = 3,500 (additional calories/week)
1,300 (calories per day) x 7 (days) = 9,100 (Weekly calories) or a surplus of 3500 calories for the week.
PSA as to why cutting 500 calories a day is a bad idea.
It's not sustainable, plain and simple.
500 calories can be a lot of food, especially if you're consuming whole/natural foods, and slashing that out of your diet can cause a lot of issues mentally adapting to it, pretty intense hunger pangs and when you decide to come off the diet your body will have adapted to that significantly lowered amount. Your metabolism changes over time and as you lose weight and provide your body with less calories, it will slow down your metabolism to accommodate, both, the lower body mass and calories. This is why you plateau. Since you have lowered your overall mass, your resting metabolic rate will have changed, meaning you no longer need 1800 calories to survive and you RMR is likely to be lower than the calories you were consuming pre-diet.
This can also lead to yo-yo dieting. As you come off of your diet and reintroduce the calories that you cut out, you'll gain back the weight you lost and then some.
For example, lets say you started with 1800 calories as maintenance, but were consuming 2000 calories a day. Realizing you were gaining weight, you cut your calories to 1500, which is 300 calories below your maintenance. You lose the weight you want and decide to go off your diet or because you went too aggressively, you get tired of the diet and kick it to the curb. So you go back to eating 2000 calories a day, but what you didn't realize is that as you lost weight, you're maintenance calories dropped to 1600 calories a day. So instead of being in the 200 calorie surplus that you were before you started your diet, you're now at a 400 calorie surplus leading to more weight gain!
A better approach is to gradually reduce your calories in a way that may leave you a little hungry but, not starving, think 100-200 calories less a day. Your weight-loss will be more gradual, but ultimately more sustainable. You need time to mentally adapt to eating less food. If you go slowly, you'll naturally reach your new RMR and when you plateau, can adjust from there, by reducing another 100-200 calories or increasing your activity to manually burn more calories.
4. What are macro-nutrients?
Macro-nutrients equate to a certain numbers of calories per gram.
1 gram of protein is 4 calories.
1 gram of carbohydrates is 4 calories.
1 gram of fat is 9 calories.
You can use this to determine which macro-nutrient a food is a good source of by doing the math. Peanut butter, for example, is routinely pitched as an excellent source of protein, but when we break it down:
1 Serving = 2 Tablespoons
8g of Carbs - 8g x 4 Calories = 32 Calories
16g of Fat - 16g x 9 Calories = 144 Calories
7g of Protein - 7g x 4 Calories = 28 Calories
Per the math, it's actually a good source of fats. Fat comprises the largest percentage of calories per serving.
Additionally, you can use tracking macros as a tool for dieting. Tracking macro-nutrients is another way of reigning in calories but, attempting to get a certain percentage of your daily calories from each macro-nutrient.
For example, if you were on a 1500 calorie diet and with the goal of getting 40% of you calories from carbs, 35% of your calories from protein and 25% of your calories from fats you would be looking at getting:
600 calories or 150 grams of Carbohydrates
525 calories or 131 grams of Protein
375 calories or 41 grams of Fat
All of that being said, you still need to be in a caloric deficit, whether you're tracking calories or tracking macro-nutrients, to lose weight.
How you end up in that deficit is up to you. It can be done through diet, exercise or a combination of the two.
In my experience, addressing diet and combining it with exercise is the most successful way to do this. It means that you are reducing your calories a little bit and increasing your deficit through physical activity.
Tracking your calories and monitoring your intake without exercise can be effective, but a slightly slower process.
Not tracking your diet and utilizing exercise alone, can be successful if you find your weight is relatively stable from day to day. This is an indicator that you are generally eating around your maintenance calories so adding a little physical activity can put you in a deficit. This approach doesn't work, however, if you tend to over-consume calories. It's extremely difficult to out-train an unhealthy diet, even if it's comprised of mostly healthy foods. Food options available to us vary widely in calorie content and not having a rough idea of how many calories you're putting into your body can lead to massive surpluses of 1000 calories or more a day, which is next to impossible to out train, unless you are achieving athlete levels of activity.