Last week I had my body fat measured by the gold standard of body composition testing: the hydrostatic body fat test.

I did this test exactly one year ago so I thought it would be informative to see the results a year later (I just checked my email and realized I received my results on January 29, two years in a row). I expected the test to be particularly illuminating this year because of the notable weight loss I have experienced in the past 12 months.

(note: This is part 2 of a 2 part post. Part 1 focuses on the testing experience and what to expect if you go in for a hydrostatic body fat measurement. Part 2 examines my personal body composition changes over the past year. For reference, the picture above shows the volume of 1 lb of fat next to a shallow, superficial coffee mug from Southern California).

I want to begin by saying that last year my body fat percentage was very low for a female, even lower than some athletic males. I am small, eat healthy and am very active so everyone expected I would test at the low end, but my body fat was even lower than any of us imagined.

At the time I did not have a body fat goal, but was very curious about my body composition given my lifestyle.

This year (again) my health goal was not directly related to body fat percentage (I will admit that I would have been disappointed had it gone up), but I have many habits–both new and ongoing–that have the potential to significantly impact my weight, appearance and body composition.

So what did I change and how did it affect me?

Let’s start with my favorite subject: food.

It has been over three years now since I have abandoned dieting and focused on healthy eating. This transition was difficult for me, because I had been on a diet for virtually my entire life (since age 11).

The most notable dietary changes I made were:

1. Greatly increasing the diversity and quantity of vegetables I eat daily.
2. Eliminating all nutrition bars, shakes and processed foods.
3. Greatly increasing plant oils and reducing animal fat.
4. Increasing plant protein and reducing animal protein.
5. Increasing whole grains.

Eating more (any) whole grains was by the far the most difficult hurdle for me to overcome. Back in 2003, I would have rather starved than eat any “carbs.”

I have lost weight every year since I changed my diet. This year I dropped (significantly) below my goal weight. And remember, this is after I stopped dieting.

But just because I no longer live on a diet does not mean that I stopped thinking and learning about food. I am constantly reading primary scientific literature and improving my knowledge of nutrition science, and it is impossible for this not to impact the way I choose to eat.

As part of my continuing education, I have further modified my diet over the past 12 months. I have completely stopped buying processed “whole grain” products like Oroweat breads and phony whole grain cereals.

From what I have learned, something is not really “whole grain” unless it actually looks like a grain, no matter what the FDA says. That is to say, the benefits scientists have discovered from whole grain foods are much more substantial if the grains are still intact rather than processed and reconstituted.

Consequently, this year I have a more diverse diet of whole grains, but still occasionally consume processed starches if I find the situation warrants an exception.

Also this year I have made a concerted effort to eat more beans and other legumes for protein. Subsequently I eat fewer animal products and do not consume dairy as part of my daily routine. Don’t get me wrong, I love cheese and creamy sauces. I eat them, but try to limit them to special occasions (like Valentine’s Day).

I have also increased my farmers market shopping from about 50% of my vegetable and fruit purchases to over 90% (I used to regularly supplement my purchases with veggies from Whole Foods and my local market) . This shift was motivated primarily by taste, health and science (local organic foods are more flavorful, more nutritious and have fewer harmful chemicals), but was also influenced by economics and politics.

Another change for me this year was my workout routine.

I used to run marathons and always believed with absolute certainty that cardiovascular workouts were the only way to lose weight. Strength training (weight lifting) was for building up muscle, I thought. I am naturally a muscular, athletic girl and always believed I had plenty of muscle and could live without any extra.

Prior to 2008 I did minimal upper body weight training at the gym, mainly assisted pull ups and dips. But I spent hours on treadmills and elliptical machines.

This year I have been too busy to spend 7+ hours a week doing cardio. I have consequently reduced my cardio workouts to 30 min per day, 5 days a week (or less). I partially make up the difference by walking to my shuttle stop for work (about a mile each way), rather than taking public transportation.

In addition to less intense cardio activity, last summer I began a serious upper body weight lifting regimen. I spend significant time in the weight room using free weight for shoulders, arms, back and abs. I am much stronger in almost every way (except cardio endurance) than I was a year ago.

Interestingly, despite the weight loss and increased strength training, my body fat percentage is exactly the same compared to a year ago (actually 0.1% less, statistically insignificant). That means while I lost some fat, I lost a similar proportion of muscle.**

It is impossible to say why the number is exactly the same, but it is an interesting thing to think about. As I mentioned earlier my upper body is noticeably stronger than it was last year, so it can only be assumed that I increased lean body mass on my upper body. However, my arms are still really small, so this probably represents a tiny percentage of my total weight.

Conversely, my legs (and, um, rear) are substantially smaller (about a size and a half at my favorite denim retailer), so based on my results I would assume that I have lost muscle in my legs because of the drop in strength-building (resistance) cardio work. The added walking does contribute to my cardiovascular fitness, but probably does not add new muscle.

Therefore my hypothesis is that my muscle mass was somewhat redistributed and my total body fat was reduced. Because I only shrunk in mass (not height) the result is a much leaner appearance overall, even though my fat percentage did not change. Although I was happy with my physique last year, deep down I would have admitted that this muscular redistribution was a goal of mine, so I am very happy with the results.

The moral of the story

If you think you need to diet, stop dieting. If you want to lose weight without gaining too much muscle, do less intense cardio workouts and increase strength training.

Five years ago I would have called you crazy if you told me these things, but seeing is believing.

My goal now is to maintain my weight and body fat, and keep focusing on my healthy diet to fight the diseases of affluence (aka diet): heart disease, diabetes, hypertension, cancer and dementia. I hope you join me.

What do you think about my fat and weight loss story?

Click here to read Body Fat Test: One Year Later (part 1)

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**I debated for hours whether or not to post my weight and body fat percentage on the internet. I decided not to for the same reason I didn’t post it last year. However, I realize that some of you are info junkies (like me) that would really love a solid number to wrap your brains around. As a compromise, I will send an email with both my weight and body fat as recorded by Fitness Wave (2008 and 2009) to anyone who makes a Paypal donation of $5 or greater to Summer Tomato. The information will be sent to the email address used for the donation unless an alternate address is given. If you have any additional questions or concerns, please email questions@summertomato.com.

This week my awesome gym (Bakar Fitness) was once again offering hydrostatic body fat testing courtesy of Fitness Wave.

I had my body fat and metabolic rate tested last year and thought it would be interesting and informative to go in for a one year follow up.

I also want to give you an idea of what to expect if you decide to “get dunked.”

(note: This is part 1 of a 2 part post. The first post focuses on the hydrostatic testing experience rather than my personal story. Come back next week for part 2).

“Hydrostatic” body fat testing is a lot like it sounds: you get weighed under water. The principle behind the method is that virtually all tissues in your body–bones, muscles, organs–weigh more than water. That is, everything sinks except fat. The density of fat is lower than other tissues and consequently, fat weighs less.

Using this knowledge you can calculate how much fat you have by comparing your weight inside and out of the water. The lighter you weigh under water compared to on land, the more fat you have. You can convert this into an exact body fat percentage by doing a little math. (Don’t worry, Fitness Wave does this all for you).

Calculations are even more accurate when you throw in measurements like height. For this test I even had my ankle size measured.

During the test you step into a tank of warm water (pictured to the right) and position yourself on a metal scale. You are instructed to blow out all the air from your lungs and submerge your head while the operator checks your weight. This process is repeated at least three times, and takes about five minutes.

The bottom line is that when packing your bag for your body fat test remember that you will get wet.

A bathing suit and towel are appropriate.

If it is January (or summer in San Francisco), you may also want to bring a change of warm clothes and sandals. When testing, the Fitness Wave trailer is stationed down near the loading docks between the Community Center and Genentech Hall at UCSF Mission Bay. You probably don’t want to walk from the locker room to the trailer in your bikini.

Hydrostatic Testing Checklist:

1. Bathing suit
2. Towel
3. Warm clothes
4. Convenient shoes
5. Healthy dose of perspective

Packing your bag is not all the planning you need to do before getting a body fat test. As I explained last year, I also recommend you decide before you go about what you will do with this personal information. Determine beforehand whether or not you want to tell your friends what you are made of to save yourself from stress and awkward conversations later on.

Overall the testing was (once again) a great experience, and I highly recommend getting a hydrostatic test if you get the opportunity. I received a print out of my numbers and an email with more information the next day.

Next time I will reflect upon how my eating and workout habits have affected my body composition over the last year. Check back next week for all the gossip.

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Click here to read Body Fat Test: One Year Later (part 2)

Have you ever had your body fat tested? Are you interested?