White and brown fat is yet another one of those topics that many people get hopelessly fixated about, along with other ‘rabbit holes’ like macro splits, meal timing, high- and low-GI foods, training pyramids and the like. Keep it simple!
The scientific term for body fat is adipose tissue. Adipose tissue forms part of the body’s complex metabolic and endocrine system that produces hormones to regulate many things such as sleep, sexual function, blood pressure, body temperature and appetite. One of the most important functions of adipose tissue is as a ‘master regulator’ of energy balance.
Adipose tissue can be categorised according to special biological functions, such as white, mammary gland, brown, and bone marrow adipose tissues. In humans, the overwhelming majority of body fat consists of white adipose tissue (WAT) and the other forms can be largely ignored.
WAT functions mainly as a fantastic energy reservoir, thermal insulator, and as a source of recently discovered hormones.
A kilogram of body fat contains about 7,700 calories (or 3,500 calories for a pound). A typical Bodyscan client (male or female) presents with about 20kg of body fat, which equates to over 150,000 calories! To find out how many calories you need to eat to reach your target, use our body composition calculator.
Increased and excessive adipose tissue mass, however, is the primary characteristic of obesity. Extremely obese individuals may have double or more (300,000-450,000 calories) that amount of stored energy. One obese individual fasted for over a year with no ill-effects (which proves that ‘starvation mode’ doesn’t exist!)
Adipose tissue can be found under the skin (subcutaneous fat), internally (eg, visceral fat around the organs) and intramuscular (between muscle fibres). Men tend to have more visceral fat and store more subcutaneous fat around the abdomen (android region) than do women, who carry proportionately more around their hips and thighs (gynoid region). The evidence indicates that body fat spot reduction is either a myth or doesn’t occur to any meaningful degree. Everybody has stubborn body fat areas.
Subcutaneous fat (the stuff you can pinch) is reduced by creating an energy deficit over a sustained period (ie, eating and drinking fewer calories than you burn).
Visceral fat will fall simultaneously. But because visceral fat is more metabolically active, it also responds directly to increased activity. So a combination of reduced consumption and increased exercise is ideal to combat both the fat you can see and the more dangerous fat that you can’t.
In summary, don’t get dragged down time-wasting rabbit holes about different colours of fat, or trying to turn one into the other. As it happens, nearly all of your body fat is ‘white’ and you can reduce it by eating a bit less and doing a bit more!
Nutritionist and Bodyscan Consultant
For most people, losing body fat is the quickest way to improve body composition and overall health. Achieving a low level of body fat will improve not only the visual aesthetic but also contribute to a reduction in harmful, visceral (internal) fat.
The issue that most face when trying to achieve this is how to maintain the muscle mass they have built up. Muscle-building is a slow, hard progress, so to see muscle disappear is dispiriting to say the least.
The most sensible step you can take to preserve lean mass when shedding body fat is to slow the rate of fat loss. The risk of muscle catabolism (muscle breakdown) goes up when you lose weight (body mass) at a faster rate. A faster rate will negatively alter the balance of muscle-to-fat loss. By slowing the rate down you can ensure maximum retention of lean mass. I recommend a rate of 0.5kg (just over a pound) of fat loss per week achieved through a sustainable calorie deficit of 550 per day.
It becomes even more important to slow the rate down as you achieve lower levels of fat. As well as being negatively impacted by rapid weight loss, muscle breakdown is inversely proportional to your total fat mass - ie, the leaner (lower fat) you get, the higher the risk of losing muscle.
So when you have more fat to lose, you can afford a faster rate without sacrificing much muscle, but as that total fat comes down, you cannot continue at the same rate. The rate must be adjusted proportional to your total fat mass.
Take a look at the (overall amazing) results for Bodyscan customer Jim below. In his first five months, he lost 20kg of fat (more than half of what he started with) and just 1kg of lean mass (a fat-loss-to-muscle-loss of 20:1). But four months after that the ratio had shrunk to just 2:1 (5.2kg of fat and 2.6kg of lean).
The graph on the left shows the three scans; the rate of fat loss (yellow) slows down while the rate of muscle loss (blue) accelerates. The tables on the right show the details for fat and lean mass, with the earliest scan at the bottom of each table and the most recent at the top. In each table look at the numbers in the far right column ('change since previous scan') .
Work to preserve muscle
The second thing you should be doing is resistance training throughout your calorie deficit to hold on to muscle. With an optimised programme of weights, calorie deficit and protein consumption you could actually increase muscle while losing fat. Or you could retain what you have or keep losses to an absolute minimum.
Without weight-training, it's typical for Bodyscan customers to lose 1kg of lean mass for every 3kg of fat. Work hard in the gym against with a small calorie deficit and you can halt muscle loss completely. Download our muscle guide to see what makes a great weights regimen.
So, in summary, to preserve your hard-earned muscle:
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