The Tests Explained
There are a range of tests that we will be doing on a monthly, weekly and a fortnightly basis; as well as at the beginning and the end of the project. Because Jeanne and I aren’t overweight and are acceptably fit, the changes that will occur over the two-month period will be minimal but they will be there.
Although this is in no way a weight loss exercise, it’s important to see what each diet does to our weight so that we can predict the trend.
FYI: Should a person gain an excess of weight in their stomach area (abdominal adiposity) they would be in greater risk for heart disease than if they gained fat in other parts of the body.
Body fat %
We will be monitoring our body fat percentage on a weekly basis using Bioelectrical Impedance Analysis. BIA is a quick and easy way to measure fat percentage based on a formula using our weight, height, age, gender and a figure from the BIA machine. The BIA machine works by placing electrodes on our hands and feet and measuring how the current is ‘impeded’ by our muscle and fat.
(The DEXA Scan is a more accurate way to test body fat percentage and will be done at the beginning and the end of the project.)
Our curiosity goes deeper as we see what happens to some vital components in our blood. This will mean that Jeanne and I will have to have a whole bunch of blood drawn at Pathcare every two weeks to track the following:
Fat is transported around the body in the bloodstream as Triglycerides which make it an interesting one to follow. A high level of Triglycerides raises the risk of heart disease.
Fasting insulin and fasting glucose
Glucose is digested carbohydrates in the blood stream and Insulin is the hormone which is released into the blood stream after eating carbohydrates that signals the liver and muscles to take up glucose from the blood stream into these tissues. This is important both to provide energy for these organs and to clear glucose from the bloodstream as it is toxic in high concentrations.
CRP is protein found in the blood. The reason why we’re interested in this is that its levels rise when there is inflammation in the body. You want to have low concentrations of CRP for lower your risk of heart disease, we’re curious to see how the diets affect us.
Glycosylated haemoglobin (HbA1c)
This gives an indication of how much glucose has been in the blood for the previous month or two. Haemoglobin is a protein found in red blood cells and HbA1c refers to hemoglobin which has a glucose molecule bound to it. Because red blood cells typically live for 8 weeks or so, measuring HbA1C will give an indication of the average glucose content of the blood over that time.
Cholesterol is a type of waxy substance that is produced by the liver and is essential for many biological processes in the human body. Some of these include:
- Construction and maintenance of the outer layer of cells
- Production of sex hormones
- Turning sunshine into Vitamin D
- Making sure our cell membranes are permeable
- Producing bile
So it’s important to understand the Cholesterol itself isn’t bad. The problem is that it isn’t soluble in blood and has to therefore be transported by compounds called lipoproteins.
Low density lipoproteins (LDL) carry cholesterol from the liver to the rest of the body and have been labeled ‘bad’, while high density lipoproteins (HDL) carry cholesterol from body to liver where it is broken down or excreted and has been labeled ‘good’.
These labels of ‘good’ and ‘bad’ are not 100% correct. To say that your LDL counts are at a ‘healthy’ level doesn’t mean you’re out the woods. LDL damages the inner lining of artery cells by penetrating them. When LDL particles are small your risk of heart disease is high even though your count may be ‘healthy’. Also, the bigger the particles there are the less of them there will be. Having the particle size of your cholesterol tested isn’t common practice and isn’t widely available. We will however be testing particle sizes for this project. Lucky us.
Now, you need to be aware that given the fact that this is only a two-month project, the effects on our cholesterol may wobble a bit. We think though that Jeanne going on the low carb/high fat diet will show the following: her LDL should increase slightly but this will lead to a more pronounced increase in HDL. This increase in HDL should lower the triglycerides in her blood and an increase in her LDL particle size. The theory being that a small increase in LDL levels is not something to worry about if other parameters are good.
Resting metabolic rate
Resting Metabolic Rate is the minimum amount of energy a body requires when lying in physiological and mental rest. (Also known as Basal Metabolic Rate). Jeanne and I will have to fast 12 hours before and then lie, completely relaxed, in a quiet room set at a cozy 25 degrees celcius for 20 mins, while breathing into a plastic bubble – kind of like a flat astronaut’s helmet. Very pretty.
The reason why we’re curious to measure this is that RMR accounts for 60-80% of total energy expenditure in many people. It’s best to have a high resting metabolic rate if your aim is to lose weight or maintain a trim figure. In fact a slow resting metabolic rate for your weight increases your risk for obesity.
FYI: The rest of the energy that people use is made up of Thermic Effect of Food (TEF) and Physical Activity (PA). TEF accounts for about 10% of total energy expenditure for a mixed western diet. This is the amount of energy used to digest, absorb and transport nutrients. PA is the energy required for the muscles to move the body and generally accounts for 15% to 30% of total daily energy expenditure. For obvious reasons it is the most variable component.
Shoulder, chest, bicep, upper waist, lower waist, hip, thigh and calf circumference
As with weight, we’re going to track our measurements to see which trajectory we’re on.
Blood pressure is the force of blood pushing against the walls of your arteries as your heart pumps blood. If this pressure rises and stays high over time, it can damage your heart and lead to plaque buildup. A nice one to track in a project like this.
The Beginning & The End
The Dexa Scan is the gold standard in measuring fat percentage. It is much more accurate than BMI or any other method but is much more expensive and has a higher risk due to the use of radiation. The bonus with this test is getting to see bone density too.
Once again, because Jeanne and I are relatively trim to start with there won’t be a dramatic change over the two-month period but we should see some difference and could extrapolate what would happen if we continued on those routes.