So, what do you think is an acceptable weight loss per week?
Two pounds? Five pounds? Ten?
Most advertising would have you believe that this number is somewhere between four and seven pounds in a week.
Ever notice that most diet advertising specifically mentions “the first month” or “the first two weeks” when they’re talking about their results? Well, there’s a reason for that.
First, realize that most of these advertisements are hawking Diets. That capital “D” isn’t a typo—it’s a differentiation. To me, there is a huge difference between a diet, which describes what foods you consume on a regular basis, and a Diet, which is really nothing more than a heavily restricted eating plan that turns into a popular fad to lose weight. (Do note that I do not think of plans that are restrictive for health reasons, like gluten-free diets for those with a diagnosed case of celiac disease, or balanced plans that someone chooses more as a lifestyle choice or for ethical reasons, such as the Mediterranean diet, vegetarianism or veganism, as Diets.)
Now, let’s look at the claims made in these advertisements. They aren’t necessarily wrong or lying, they’re just not telling you the whole truth. You can lose up to seven pounds in a week on a highly restricted diet. Here’s the issue: you’re not losing seven pounds of fat in the first two to four weeks.
Remember that fat is one of your body’s forms of long term energy storage. However, it is not your body’s only form of energy storage. Muscle mass can also be considered a long term energy source. However, under slow, long term deficits, your body prefers to burn fat and preserve muscle mass. Under high stress starvation conditions, muscle is metabolized at a much higher rate.
Your body also has a “medium term” energy storage form called glycogen. Usually, this is stored in your muscles and your liver. The average person has about a pound of glycogen. It is mostly stored in the liver and muscle.
Here’s the thing about glycogen: it also holds on to water in a 3:1 to 4:1 ratio (the numbers vary depending on the study you look at). For every pound of glycogen, your body also holds on to 3 to 4 pounds of water. So the average person will have anywhere between 3 to 4 pounds of water weight that is just associated with glycogen stores.
So in total, your body has about 4 to 5 pounds of weight associated exclusively to “medium term” energy storage. Thus, what happens when those stores are depleted?
Congratulations, you just lost 4 to 5 pounds…Which, unfortunately, will come right back when your body replenishes its glycogen stores.
Then what depletes glycogen stores? Exercise, starvation or any form of calorie deficit will do it. But extreme deficits tend to deplete it faster.
It is also my observation in my clinic that an additional 5-7 pounds is lost through water weight changes and waste excretion that’s associated with intense weight loss. So, if we go on an intense diet or exercise program, we can expect to lose about 1 pound of glycogen and 5 to 10 pounds of water and waste products.
“But Dr. McGuire,” you say, “surely some of the weight loss from those Diets is fat, right?”
Yes. Absolutely. Your body does not completely deplete glycogen then move to burning fat when on a calorie deficit. It’s all done at the same time. However, the actual amount of fat burned is about one to two pounds per week depending on your calorie balance.
That number really comes down to human physiology. In most weight management circles, you’ll hear something called the “3500 rule.” This “rule” states that it takes 3500 calories to burn a pound of fat. Now, there’s all sorts of debate on the actual validity of the number—some say it’s lower or higher than that based on an individual’s metabolism. But that’s another discussion entirely. Yes I know some of you are rolling your eyes at this. Remember, it is a rough estimate but it’s a fairly accurate prediction of long term weight loss (plus or minus 5%).
So, for someone to lose a pound of fat a week, they need to have a daily calorie deficit of roughly 500 calories. For someone to lose two pounds a week, that number is doubled to 1000 calories.
Which sounds doable, until you take into account that most individuals have a BMR (basal metabolic rate) of about 1200-2000 calories per day and a TDEE (total daily energy expenditure) of anywhere between 1400-2400 calories depending on their BMR and activity level.
Thus, to lose two pounds a week through dietary restriction alone, the average person will be eating anywhere between 400 to 1400 calories a day.
And here’s another addition to consider: with extreme calorie depletion, your body begins to metabolize muscle mass on top of burning fat. So, females need to consume at least 1200 calories per day and males need to consume at least 1400 calories per day to minimize potential muscle loss.
Are you starting to see where those advertising claims begin to fall short? What those advertisements fail to mention is that after the first two to four weeks, your weight loss slows to one to two pounds a week if you remain on the program. Which usually leads to frustration because most people don’t know that the slow-down is coming.
So here’s the my main takeaway: keep your expectations realistic. If you are losing one to two pounds a week, fantastic.
I recently had a patient approaching a 70 pound weight loss over the course of a year. That’s an average loss of 1.3 pounds a week.
This patient told me something that really hit home. She said that I was the first person to make her feel successful for losing one to two pounds a week rather than making her feel like a failure for not losing five to ten pounds a week. Now, she’s within twenty pounds of her target weight and is more determined than ever to stick with her lifestyle change.
Safe and effective weight loss is a marathon, not a sprint.
There is a reason that my program and others like mine take a year or more. It takes a lot of education to mentally reprogram all of the unrealistic expectations that people have when it comes to weight loss.
But, if you start with the expectation that one to two pounds lost in a week is a success, then you’re much more likely to continue down a healthy path to a much healthier lifestyle. And you can lose anywhere between fifty-two and a hundred and four pounds in a year.
As I tell all of my patients: God-willing, we’ll still be here in a year. Why not be here fifty pounds lighter?