How to Properly Design Your Diet – Part One

Two of the questions I get asked most often are “what should I eat” and “how much should I eat if my goal is (insert goal here)”.  This is a very complex topic and one that I have a tough time answering in casual conversation due to the depth in which I want to take it.  I’m going to try and address this topic in greater depth here, realizing that I will likely only scratch the surface.

When designing any diet, it always helps to understand how much energy intake is required to maintain a stable body composition (note: I did not use the term weight on purpose and we may or may not delve into why I didn’t later).  Most folks do not have access to use the more scientific methods such as doubly labeled water and respiration chambers so we are left to other methods that are accessible to everyone.  Luckily, finding a fairly accurate energy expenditure rate isn’t too difficult at all.

For those that are gadget geeks, there are products on the market that are advertised to do most of the work for you.  Some of the more popular and complete gadgets include BodyBugg and BodyMedia.  These products are worn on the skin, often via armbands, and measure various data points related to the body to calculate caloric expenditure – such as skin temperature, movement via accelerometer, and heat flux (the rate at which heat leaves the body).  Although they have been proven to be pretty accurate, most cost a fair amount of money up-front and also require a subscription fee to take full advantage of all their features.  Because this post will be geared towards those not wanting to pay this high cost for something you probably will only need a few times, I will not refer to these products beyond this point.

Fortunately for frugal individuals such as myself, there is no need to plunk down money on a gadget if the individual is up for a little legwork.  Before we get too far into this, there are some terms I might be using throughout these posts that are important to understand.

It is also worth mentioning at this point that no two individuals will be exactly the same and the intended audience of this article is adults; pubescent teens are out of scope.  Teenagers should largely not focus on minute details such as caloric allowance anyway in most cases.

So, now that we understand some of the basic terminology, we’ll want to put it to use.  In other words, how would an individual calculate their total energy expenditure so that they have a good baseline figure which will allow them to design their diet to match those requirements (also sometimes called maintenance calories)?  There are many schools of thought but I always recommend creating a baseline intake figure and then potentially adjusting that intake figure as required after a few weeks of careful monitoring.  So how do we derive the initial baseline intake figure?

Fortunately for us, some smart science-types have already created formulas that allow us to take our first swag at it.  Some of the more popular formulas you’ll run into include the Harris-Benedict, the Mifflin-St. Jeor, and the Katch-McArdle.  I’m going to focus on the Katch-McArdle formula as it is the most accurate of the three and what I personally use when helping individuals.  To get an accurate Katch-McArdle figure, you’re going to need a reasonable guess as to your current body fat percentage.  For anyone not familiar with calipers, become familiar before reading on.

That’s it for this time, in the next post we will put Katch-McArdle to real-world use and talk, in detail, what we do once we have our first, baseline caloric figure.