I can remember in college always wanting to weigh 120 pounds/54.4 kg. At 5 feet 4 inches/162.5 cm, that would give me a BMI of 20, which is in the “normal” range, 18.5–24.9.

I had been a competitive high school athlete and hated my large thighs, which I attributed to years of playing soccer. What I didn’t realize at the time was that my legs were pretty much solid muscle and my goal of thinner thighs was unrealistic and unhealthy.

Women need a body fat percentage of at least 10–12% for general good health. But it can be very dangerous to have only this much body fat, as body fat is essential to protect your reproductive organs and bone health.

Maintaining a very low body fat for a prolonged period will affect your hormones and your menstrual cycle, which could lead to infertility.

If you want to have regular menstrual cycles, you need a body fat percentage of at least 13–17%. “What about those ladies who compete in bodybuilding figure competitions?” you might ask. They often will drop down to 15% for the week of their event.

This weight is not maintained after the competition day itself—trust me. If you meet one of these women during her off-season, you will be shocked at how much her body changes when a competition is not in sight. For me to be 120 pounds/54.4 kg (my college “goal” weight) with 15% body fat, I would have had to lose an additional 10 pounds/4.5 kg of muscle.

Do you see why my original goal wasn’t realistic now? I didn’t realize this conclusion until after I trained with a personal trainer for 4 months, twice a week. We planned to do a before-and-after video to show that strength training doesn’t create bulky muscles in women. He regularly measured my body fat, and I followed a fairly healthy diet.

I couldn’t sleep the night before the final weigh-in because I was so hungry. I wanted the video to be good; I needed to shock the viewer. At 127 pounds/57.6 kg, I measured 14.7% body fat. I was this weight for maybe 1 day because my body was dehydrated.

We did this on purpose so that my muscles would “pop” on camera, something the women in figure competitions have mastered for the day of their event as well. We lied on camera to say that I weighed 129 pounds/58.5 kg because we did not want to promote the fact that I had dropped below the recommended 15%.

We shot the video and titled it “How I lost 100% of My Excess Body Fat.” Currently, the video has over half a million views, but I wish I could add a disclaimer that I gained back 5 pounds/2.3 kg pretty quickly after we finished. My body weight was too low to sustain my lifestyle.

I craved carbs and fat incessantly until my body gained back those extra pounds. At just 5 pounds/2.3 kg heavier, I was able to have my occasional treats and wine while maintaining a weight I was comfortable with. Female athletes typically have between 15% and 20% body fat, and typical gym enthusiasts have up to 24%. As much as 32% is considered healthy for a female. Without knowing your body fat percentage, your happy healthy weight may be a challenge to calculate.

I’m not a fan of bathroom scales—I find most of them to be very inaccurate. A skin-fold measurement with calipers is one of the most accurate options but needs to be done by a skilled, experienced professional. The most simple option would be to grab a tape measure and calculator.

I’ve also had mine calculated at one of the top gyms in the United States, Peak Performance in New York City, standing on a highly sophisticated scale with a built-in body-fat monitor that you grip with both hands.

If you have access to something like this, then by all means take advantage. If you want to know the best time of day to work out to lose weight, the answer it not crystal clear. It really depends on you! I highly recommend working out in the morning, as it sets the tone for the rest of the day.

It also allows you to burn a little more fat if you do it first thing on an empty stomach. For some people who have long commutes or early jobs, this may not be a possibility.

Some people are not able to work out with the same intensity in the morning as they might in the afternoon. Afternoon is just as effective; however, things may come up during the day that cause you to bail on your workout if it’s scheduled later.

You also have more time to make excuses not to do it. Working out after dinner may disrupt your body’s ability to fall asleep easily. That is not true for everyone, though. You have to see what works for you.

A workout at a specific intensity will burn the same amount of calories whether it’s done morning, noon or night