Eating for Fat Loss
The distinction between fat loss and weight loss
The title of this article says ‘fat loss’, not ‘weight loss’. This distinction is not merely an exercise in semantics; it represents the most fundamental difference between the athlete and the non-athlete.
Weight Loss
The diet industry and the diets it produces are designed for weight loss. Weight loss includes not only fat, but also water and more importantly muscle mass. A program that has a quick start element will utilise the fact that water is lost whenever a person switches to dietary restriction aimed at weight loss to give the illusion of progress.
The athlete and commercial diets
Because commercial diets are aimed at weight loss they are not suitable for the athlete. They will not preserve hard earned muscle, nor are they designed to ensure adequate hydration status – and as such will negatively affect not only athletic performance, but also how the athlete feels and performs generally.
A quick guide to some popular diets:
The Atkins Diet: This is a low carbohydrate, high fat diet. It has high levels of protein, but is not designed as a high protein diet. Low levels of carbohydrate are problematic for the athlete; performance drops quickly as glycogen stores are depleted and not replenished. With glycogen depletion, the body will switch to an alternative fuel source, ketones to survive. The body is designed to run on glucose, and uses ketones as a backup source of fuel; the brain in particular runs best on glucose and slowly switches to ketones for fuel because running on ketones negatively affects its performance.
Muscles will breakdown muscle tissue to provide the glucose they need, when not running on fuel from fat stores (typically muscle is broken down for explosive bouts and to provide the fuel for fat mobilisation). Red blood cells only run on glucose, so maintenance of their function requires the breakdown of precious muscle. In addition to depleting muscle, and negatively affecting cognition and mood, the Atkins Diet is low on fibre which often results in constipation. It is also low in vitamins and minerals – further hitting your body’s capacity to function normally, while being high in saturated fats which are not good for either the heart or general health.
Very Low Calorie Diets: As the name suggests these are diets with low daily calorie totals – usually below 1000 calories per day, some may be even lower. They don’t tend to emphasise a particular nutrient, instead they are calorie focussed. These diets do not provide the energy, protein or fat content for optimum performance. The body will breakdown muscle tissue along with the fat to survive. This type of diet has the added complication that low calories will signal to the body that there is a famine, resulting in a slowdown of metabolic rate. The net result is that body tries to hold onto all tissue to survive and slowing metabolism helps achieve this. On a very low calorie diet you will be very tired and sleepy as the body tries to protect itself until food becomes available. The lack of fuel will not only hit athletic performance but also cognitive ability and recovery – when food is available again the body will have a lower metabolic rate and a propensity to store fat ready for the next famine. This result is why people after severe calorie restriction put on weight quickly and need even more dramatic restriction to achieve any future losses.
Single Food Group Diets: These are a spin on calorie restriction; achieving the overall calorie reduction by focussing on a single food, such as cabbage soup. These diets are usually bordering on very low calorie, and their single food group bias means vitamins and minerals are very lacking. The gut can take a real battering trying to cope – resulting in gas, diarrhoea, bloating and other unpleasant effects. Needless to say single food groups do not provide the nutrients an athlete requires; in fact often they fall very short of the requirements of the sedentary individual.
Low Carbohydrate Diets: Such as the South Beach diet – these are popular because they don’t have the high fat content of the Atkins and are so better for general health. The biggest drawback is that they are designed for a sedentary population not athletes and as such lack the ingredients and calories for athletic endeavour.
Ketogenic Diets: These are very low carbohydrate diets designed to induce a state called ketosis. Ketosis means that the body is using ketones instead of glucose for fuel. Ketosis happens in starvation as a means to survive. Ketones are sub premium fuel and result in sub premium performance. The body can run on ketones, and weight loss can be impressive using this technique. However, glucose is essential and when the body has no stores and insufficient consumption to meet demands it will breakdown muscle tissue to provide it. It will also slow metabolic rate in order to protect itself. The ketogenic situation is not conducive to optimum performance or recovery.
Macro-biotic Style Diets: These are dietary restrictions and are very unlikely to give the nutrient profile that an athlete requires. These too tend to be very low in calories – restricting intake below the level an athlete requires to perform at their best or even close to it.
Note on vegetarian and vegan diets: Athletes can follow these diets and perform very well; indeed some top athletes do. Vegans face the biggest challenge because protein, iron and vitamin B12 are readily available from meat sources, and calcium is readily available in diary products. A vegan athlete may find supplementing with calcium, iron and B12 beneficial. To ensure adequate protein consumption the vegan athlete has to get a good variety of foods in their diet; notably beans and pulses so that a complete spectrum of essential amino acids are available.
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