Basal metabolic rate and weight loss
By Dr Sophie Duggan
How a few small changes to your lifestyle can make a big difference to your waistline.
You wouldn’t design a car unless you understood how an engine works. You wouldn’t construct a twenty-storey building unless you knew a thing or two about structural engineering. And yet most diet plans are put together by people with no understanding of a process that is fundamental to weight loss: basal metabolic rate.
Basal metabolic rate – put simply – is the amount of energy that your body uses, when resting, to stay alive. It can account for between 40% and 70% of your daily energy requirements, depending primarily upon your age and muscle mass. This is because as we age, we lose muscle mass. Muscle tissue uses more energy at rest than fatty tissue, so when our muscle mass falls, so does our basal metabolic rate.
Age, of course, is something none of us can change; increasing muscle mass, on the other hand, is well within our control, as studies of resistance-based exercise and time-restricted eating both show.
Resistance is useful
In an experiment at Purdue University, Indiana, 16 female volunteers aged between 67 and 69 followed a very low energy (500 calories per day) diet for 11 weeks. During that time, half of the volunteers carried out three resistance-training sessions weekly; half remained sedentary. At the end of the experiment, researchers found that while all 16 women lost weight, fat-free mass (muscle mass) was lost only in the sedentary group.
Many other studies have shown the same results, even without dietary restrictions. At the University of San Antonio, for example, a group of 47 volunteers aged between 67 and 75 were divided into two groups: 27 underwent resistance training three times per week over 12 weeks, and 20 did not engage in any resistance training. All volunteers ate normally throughout. At the end of the 12-week period, members of the resistance-training group had significantly decreased their fat mass and increased their muscle mass.
Flip the switch, boost your Basal Metabolic Rate
Resistance training, then, is key to increasing your basal metabolic rate. But like an engine, the performance of your basal metabolic rate depends on a range of factors. For this reason, at the Fast800, we are also passionate about time-restricted eating (TRE), which involves limiting the period during which you eat to 12, 10 or even 8 hours per day.
A growing body of evidence shows that the longer you wait between the last meal of one day and the first meal of the next, the more deep-level repair work your body is able to accomplish. During periods of fasting that last for more than a few hours, the body stops burning glucose and starts burning fat, or “flipping the metabolic switch”, as some scientists have termed it. Amazingly, the process of switching from glucose to fat triggers an array of damage-reversal pathways, including the protection and growth of muscle tissue.
It is thought that this takes place is because muscle cells, during the fasted state, depend on droplets of fat stored inside muscle tissue itself – and so in order to protect essential energy supplies, the body conserves muscle.
Basal metabolic rate and food
Basal metabolic rate depends, then, on optimising muscle mass – which, in turn, depends on resistance training and TRE. But however much you train or fast, you’re not going to build good-quality muscle if you are not taking in good-quality food.
For the purposes of an ideal basal metabolic rate, there are three essential nutrients to focus on: protein, B-vitamins and blood-builders.
1. Protein: quality and quantity
In order to build muscle, the human body needs 20 different amino acids. Eight of these have to come from food, as the body cannot synthesise them. Large amounts of protein can be harmful though, and so it is much more important to eat a moderate but varied amount.
2. B-vitamins: unlocking energy from food
Driving your basal metabolic rate depends not just on creating and feeding energy-hungry tissue, but also on being able to convert the food that you eat into energy it can use. This is where B-vitamins are essential. The powerhouses of your cells, termed mitochondria, use a set of enzymes to break down glucose and fat molecules and release energy; these enzymes, in turn, need a plentiful supply of vitamins B1, B2, B3, B5, B6, B7 and B12.
To stay stocked up on B-vitamins, you will need to eat fresh green vegetables, eggs, yeast, mushrooms, dairy products, lean meat, oatmeal, lentils, whole grains, soy and avocado. If you are a vegetarian, you’ll need to source extra B-vitamins from non-meat foods.
3. Blood-builders: iron and folate
To burn fuel, your body also needs oxygen, and to supply your mitochondria with oxygen, you need healthy red blood cells. This means making sure that you take in enough B12, folate (another B-vitamin) and iron. Folate is present in all green leafy vegetables; iron is most easily absorbed from meat, but is also found in a range of plant sources as well.
At the Fast800, we do things differently. Losing weight is one of the biggest commitments that you can undertake, and so we take your results as seriously as you do. Working with a hand-picked team of experts, we stay up-to-date on advances in nutrition, medicine and sports science, ensuring that our weight loss plans enable you to achieve lasting success in minimal time. Interested in finding out more?