Eat less than you burn and you’ll lose weight – it’s preached as the “be all, end all” of weight loss and it’s completely WRONG.
The truth is, the number of calories you eat is not the only factor that affects your body composition.
In fact, there are at least 5 other factors that need to be considered, including:
- The thermic effect of the food ingested. The thermic effect of food (TEF) measures the amount of energy that is required to support the processes of digesting, absorbing, and assimilating food nutrients as well as the energy expended as a result of the central nervous system’s stimulatory effect on metabolism when food is ingested. Of the three macronutrients, protein carries the highest thermic effect.
- The fibre content of the food ingested. Due to its chemical makeup, fibre is classified as a carbohydrate; however, it is unlike other carbohydrates in that it is a mostly indigestible nutrient. Even though each gram of fibre contains four calories, these calories will remain undigested and will not be absorbed. Therefore, if one were to consume 300 calories of red beans (a food in which nearly 1/3 of the caloric content is from fibre), approximately 100 of these calories would pass through the intestinal tract undigested.
- The glycemic and insulin index of the food ingested. The glycemic and insulin index are scaled numbers that refer to how quickly a particular carbohydrate source enters the bloodstream as sugar and how much insulin is needed to rid that sugar from the bloodstream, respectively. Generally speaking, there is a positive relationship between the two; that is, the quicker sugar enters the bloodstream, the more insulin is needed to rid that sugar from the bloodstream. When high levels of insulin are present within the blood, fat burning is brought to a screeching halt, which is anything but desirable for those whose goal is just that.
- The macronutrients present in the food ingested. Although insulin’s primary function is to shuttle glucose (sugar) into skeletal muscle, it also carries many other nutrients to their respective storage sites; this includes fat. Since carbohydrate ingestion stimulates a large insulin response and fat ingestion gives rise to blood lipid levels, the two, when consumed together in high levels (especially in the absence of protein), promote the greatest fat storage.
- The timing of the meals ingested meals. Ingesting a large amount of simple carbohydrates before bed spikes insulin, sabotages overnight fat burning, and increases fat storage during sleep. On the contrary, consuming a great deal of calories early in the day does not bring about this problem; rather, these calories are likely to be used as energy to support daily activities.
- If you lose a lot of weight, your fat cells shrink, but they do not disappear. The average adult body has between 40 billion up to 100 billion fat cells, which may sound scary. The good news is that you can still lose weight after your fat cells swell and multiply; in fact, when you lose weight, your fat cells shrink. Although their total number only decreases slightly (if at all), the cells become less metabolically active and remain in your body, waiting for you to pick up a bag of pork rinds so they can expand again. This means that it's better to try to maintain a normal weight than to gain and lose weight on fast, "quick fix" types of diets. Someone who has maintained a normal weight (i.e. has been relatively thin) all their life will have an easier time staying at that weight than someone whose fat cells have swelled and multiplied. This explains the "yo-yo effect" many binge-dieters endure over and over again.
As you can see, someone could be eating a relatively small amount of calories daily, but at the same time promoting a great deal of fat storage by:
- making poor food choices
- eating carbs and fat together in large amounts without protein, and
- consuming meals at inopportune times
- "yo-yo-ing" their commitment to losing weight
To illustrate this further, let’s take a look at a Harvard study conducted in 2000 by Robert Hugh Demling et al which analyzed the diets of 38 police officers. Demling found that although the officers were consuming a hypocaloric diet (fewer calories than they burn), they all had unhealthy levels of body fat and had been gaining fat mass over the past five years.
If all you had to do to lose fat was consume fewer calories than you burn, then these individuals would be losing fat, not gaining it! And to confirm the importance of the factors that I previously mentioned, let’s take a look at some of the other things that Demling noted:
- Only 15% of their diet consisted of protein, the macronutrient with the greatest TEF.
- Their diet contained very little fibre.
- Over 50% of their carbohydrate intake was derived from simple sugars, which have very high glycemic and insulin indices.
- The majority of the meals were high in fat and carbs with little protein
- They ate infrequently, only 10% of their caloric intake was consumed at breakfast, and over 50% was consumed right before bed.
By now, it should be obvious that fat loss isn’t just a matter of calories in, calories out.