SBSI as a simple measurement of health

It would be fantastic if there was a single number out there which you could use to say “I am n healthy”, knowing that you could improve n and directly improve your health.

One attempt at that is the body mass index (BMI) that doctors use to state generally that someone is overweight or underweight. However, the BMI values can be wildly inaccurate depending on your body type – whether you are male or female, European or Asian, active or sedentary.

BMI calculates purely on the weight and height of the person. This gets you a figure that is a good start. For example, my height is 168cm, and my weight this morning was 73.7kg. That gives me a BMI of 26.1 which is classed as “overweight”.

But what does “overweight” mean? When something is “over” or “under”, that means there is an ideal number that should be looked for. When someone says that “your BMI indicates you are overweight”, what they mean is that “an average person with your height and weight has a higher mortality than an average person with your height and a lower weight”.

Of course, no-one actually is average. I have short legs, for example. If they were 4cm longer(172cm) and I had the same weight (73.7kg), I would have a lower BMI (24.9) and no longer be considered overweight.

Some people are sedentary and have fat around the torso, while some people may work out a lot. If my weight was due to extra muscle instead of extra fat, would I still be overweight? Having less fat on the body means that I would be less likely to develop diabetes or heart diseases, so that means that even though the BMI suggests that an athletic 73.7kg 168cm man is overweight, he would actually be more healthy than a sedentary man who weighed 66kg and was considered “normal” weight.

Because the BMI was supposed to be based on the fat content of the body, it makes sense that a more accurate measure of that fat content would take these differing physiologies into account.

The Surface-Based Body Shape Index (SBSI) is a calculation which provides a more accurate index of fat content. It was published in 2015, based on data from 11,808 healthy adults, and provides a much more accurate prediction of health than the BMI does.

To measure the SBSI, you need to measure your height, weight, vertical torso circumference and waist circumference. The first two are used in BMI calculations as well, but the later two give a more discriminate calculation, for example in the case of people with shorter legs *ahem* (affecting the vertical torso circumference), or who are athletic instead of sedentary (affecting the waist circumference).

After calculating the index (here’s an online calculator), you will have a number. That number is the SBSI.

According to table S1 in the research paper, healthy people have an SBSI of .105 (female) or .108 (male).

That number is a general indicator of health. A definite number to be aimed for, rather than a range of weights that might be right or not.

Mine at the moment is .113, so I need to work on getting that down to .108.

My goal at the moment is to work on getting my weight down to 66kg anyway, even though there is no definite reason for that, but while working towards that, I will also be working on reducing my waist circumference to 84cm.

Just a thought, but I wonder if it’s possible to come up with a formula, using the data from that report, that instead of just giving a general fat content index, can accurate predict the percentage chance of death within the next 5 years? Hmm…

Jimmy Joy

A while back, I paid for my first month’s supply of Jimmy Joy, a 100% nutrition “future food”. It cost €150 for 30 day’s worth, and took 7 days to arrive. That averages out at about a €5 per day food bill. €35 per week. That’s slightly below the average food bill for a person living in the EU. Similar foods include Soylent and Huel.

The point of the food is to give you all the nutrition you need (that we’ve figured out so far), with as little effort as possible.

I’m not much of a foodie – the number one criteria I have for food is that after I eat a portion, I should not need another portion for a while. So, my “ideal” meal until now has been to make a bowl of curry noodles, and a sandwich with Marmite and jalapenos to go along with it. No-one likes my cooking – you can see why! I’m more into the efficiency of the thing than the art of it.

The Marmite is a clue as to why I needed to go onto this stuff. I’ve been vegetarian for more than a quarter of a century, vegan for about three years, and I never paid much attention to the diet. So, I ws diagnosed B12 deficient last year.

B12 deficiency takes a while to kick in, so it’s not something you notice as being wrong with your body. It’s something that gradually affects the body but that you think of as “this is fine” all along. Kind of like the story of boiling a frog – it will happily sit in a pot of water that is slowly brought to the boil, not noticing the temperature, because it’s not drastically different than a few seconds before.

I’d been tired for years, to the point that for some long periods, I would come home from work and go straight to sleep on a couch for a few hours. Doctors couldn’t point to anything specifically, even after blood tests. My arms and legs would also tingle every now and then. Especially if I had applied weight to certain parts of them. I passed this off as nerves being close to the skin.

Eventually, one blood test indicated I was very deficient in B12, and I was put onto shots. Not pleasant. I have a phobia against needles going into veins or joints. Blood tests are done at a vein and joint (elbow), while shots go into a joint (shoulder muscles).

So, that’s when I added Marmite to my diet.

Lately, I’ve noticed that I feel restless at night. I’ve self-diagnosed this as restless leg syndrome (iron deficiency), but have not done tests to confirm this.

Since starting to write this book, I’ve learned a lot about what can go wrong with the body if it’s maltreated for too long. One of the points of the book is to try find the most efficient way to stay healthy (no leaping about for hours or careful balancing of 30 food types, etc).

Nutrition-wise, you really can’t get better than using future foods. They’re designed from the ground up to be 100% of what the average adult needs. What I love most about them, though, is that I don’t have to think about it. I just mix the stuff and drink it.

Of course, once something comes to my attention, I tend to start analysing it to see if I can optimise it somehow.

Jimmy Joy is designed to be 100% perfect for the average adult. No-one is average, though, so everyone needs to adjust it slightly. In most cases, people just use it as a breakfast or main meal and “self-adjust” their diet for the rest of the day. In my case, I’m trying to figure out the optimal amount to eat that will keep me at my ideal weight.

I measure my weight every morning without fail, stepping onto the weighing scales multiple times until it agrees with the previous figure (the first time I step on a scales in the morning, it seems to over estimate my weight by almost .5kg).

I weight 74.5kg at the moment (average for the last 7 days), and my optimal weight according to BMI is 62kg.

Everyone is different, so saying something like “eat 2500kCals and you’ll stay steady” is almost certainly false. I live a sedentary life, for example, spending most of my day sitting at a computer. Others might walk around a lot, or run, or pick things up, etc. Each of these things affect your calorie usage.

With a “normal” diet, it is hard to design a balance of foods that will give you a constant weight loss or gain, or keep you at your current weight. As I said above, there is no single ideal number of calories to consume, and even if their were, the calculation needed to make sure your diet hits that and is nutritious is monumental.

It’s much easier to just adjust the number of scoops of future food you take each day.

The instructions on Jimmy Joy bags say to take 3.5 scoops and 500ml water, three times a day. I’m doing about 3 scoops three times a day at the moment and adjusting up or down over the weeks as my weight changes. I don’t want the weight change to be sudden, but I do like to see definite numbers.

Ideal body weight is something I haven’t yet tackled in my book. I’m taking the BMI scale as gospel for now, so I have a goal of 62kg to hit.