Catherine Ko, MS, RD, CDE On your never-ending journey towards those pesky weight-loss objectives, it’s important to keep your end result in mind. Sometimes it’s hard to stay focused on that magic number, but we can achieve this goal by asking a very simple question. Sure, it might have a complicated answer, but let’s consider the following :
1. Body Mass Index (BMI) BMI is the acronym for Body Mass Index. BMI is your weight (kg), divided by your body height squared (m^2). This is the current clinical standard for classifying someone as “normal”, “overweight” or “obese”.
2. Ideal Body Weight (IBW) Ideal Body Weight is a lesser known metric. Historically, this was developed by life insurance companies, as a way to predict the mortality rate. The formula is as follows:
For Males:
IBW = 50kg + 2.3kg for every inch over 5 feet
For Females:
IBW = 45.5kg + 2.3kg for each inch over 5 feet
If your BMI <18: You are considered underweight
If your BMI is 18-25: You are considered normal
If your BMI >25: You are considered overweight
If your BMI >30: You are considered obese and
If your BMI is 35+: You are considered morbidly obese
You are considered at an “ideal” weight when you are within +/- 10% of IBW
Interestingly, this is the most vigorous standard. Here is an example:
A woman is 5’6” and has an IBW of 59.3kg (or 130.5 lbs). This IBW rating translates to a BMI of 21.3. This is considered perfectly normal, but on the skinny end, in our societal standard.
3. Adjusted Body Weight (AjBW) Adjusted Body Weight is a derived from IBW, but is used mostly for clinical calculation to determine dosages or nutrition requirements, when someone is considered morbidly obese.
AjBW = IBW + 0.4 (actual body weight – IBW)
(* the factor of 0.4 can be adjusted according to the purpose of calculation)
In theory, a person should have a BMI within 18-25. This adheres to the +/- 10% requirement for an ideal body weight. Before you whip out your trusty calculator, let me just say that these are merely formulas. Someone can be very muscular, bloated, pregnant or have a high level of water retention during this calculation. Numerous conditions affect our weight and may not be a true indicator of how much someone should weigh. These formulas are predictors of what is considered ideal. This is by no means a mandate that you should or must weigh within this range. It’s important that you keep the following goals in mind, as they are much more dynamic, feasible and practical goals:
- Crank it down a notch
Once you are considered “overweight”, BMIs are classified by increments of 5. Conversely, when someone improves their BMI by 5, they will move down a step on the BMI chart. It doesn’t matter if you are barely overweight (BMI = 26.1) or morbidly obese (BMI = 43.6), make it your objective to bring it down a notch on the chart. If you have a BMI of 33.2, find out what it takes to get to a BMI of 30. Make that your goal.
- Focus on percentages
Studies have shown that weight loss is beneficial to your health. Obesity triggers chronic inflammation and it’s this inflammation that is the root cause of numerous common health problems, like diabetes, high cholesterol, cancer, rheumatoid arthritis and more.
Losing 5 to 10% of your body weight is enough to start producing great health benefits. It’s important to keep this in mind. I’ve met too many people who will simply let their diet go because they think the situation is too far gone. Losing 5% of your body weight is an attainable goal that isn’t intimidating. If you currently weighed 300 lbs, losing 15 lbs doesn’t seem like an impossible feat.
- Watch your rate of weight loss
Your recommended rate of weight loss is centered at 1 to 2 lbs per WEEK. I see the common mistake of people taking the plunge and going “all in” towards changing their lifestyle. After that initial push, they start to get discouraged because they are “only losing one pound”. Remember that it took you years to add on these pounds. You aren’t just going to magically get some exercise, eat right and see instantaneous results. It takes diligence and persistence. Losing 1 to 2 lbs per week is another attainable goal and nothing to look down upon. Consistently dropping those few pounds shows long-term commitment and does a lot to build up your confidence. Losing 1 or 2 pounds is definitely better than zero or actually gaining. Any lost pound should be considered a weekly victory.
- Weight maintenance
It should be common knowledge that your metabolism slows down as you age. In combination with other lifestyle factors, it is only by default that people gain weight over time. If a person conservatively gains 2 pound per year from the age of 18, that is 60 pounds in 30 years.
How much weight have you gained since graduating from high school? Weight maintenance is grossly underrated. It doesn’t matter what your current BMI rating is at. If you have maintained a consistent weight in the last 5 to 10 years, since entering adulthood, you’ve done an excellent job!
- Weight at age of 18
People come in all different shapes and sizes. There is no point in pursuing a “normal” BMI, if it is not your natural physique. How much you weighed at 18 years of age is a great end goal weight to achieve during your current pursuit. By keeping focus on your short-term benchmarks, eventually over time, you will gain momentum and confidence, while hitting that “18-year-old-you” weight.
