As mentioned above, dietary strategies aimed at weight loss sometimes have a very detrimental influence on post-training recovery. Sometimes, they can also lead to an increased risk of injury. Finally, if pursued incorrectly, weight loss can be a temporary change in body composition. Guidelines should therefore be given on how the amount of calories to be consumed should be adjusted in order to reduce body weight.

The two phases of weight loss

  The weight loss process essentially consists, as far as the quantity of calories is concerned, of a controlled cut aimed at creating a negative balance between calories consumed and calories introduced. The effectiveness of this strategy (or any other), for reasons that will be seen in detail below, can only be of limitedduration: one will manage to lose weight for a few weeks, but then, no matter what one does, the weight loss will stop. Here, a new phase of the diet will have to be introduced, not directly aimed at reducing body weight, but oriented towards creating those hormonal prerequisites necessary to restart the process that was interrupted before.

The calorie cut

  Now, the relationship between body weight and calorie intake is trivial and obvious:

1. if you consume calories in excess of your needs, your body weight increases;
2. if you consume fewer calories than you need, your weight decreases;
3. if you consume as many calories as you need, your body weight remains the same.

In light of this, it might seem that if you want to lose weight, it is enough to eat less in order to reduce your calorie intake compared to your needs. In reality, this is only true within certain limits. In fact, even disregarding the considerable effects that food has on body composition regardless of its ability to provide calories, reducing calorie intake too much may not have the desired effect on body composition. Many people have experienced at first hand the great limitations of the indiscriminate calorie-cutting ‘strategy’, encountering premature blockages in the slimming process, as well as the ever-discouraging yo-yo effect (i.e. the rapid recovery of the fat mass lost once the calorie-reduced diet is discontinued). Moreover, calorie cutting, if carried out in an ill-considered manner, even if it leads to a (temporary) reduction in body weight, will, on the one hand, result in a rarely sought-after partial loss of the lean component of the physique and, on the other hand, significantly reduce the energy available for training and competition. The risk of injury will only increase and performance, instead of increasing as a result of the weight reduction, will be reduced due to the side effects of the calorie cut. The needle of the scales, therefore, will tip against athletic performance and the safety of those who seek it. In the following, I will show why this happens and how to adjust the amount of food to be consumed (and thus the calories to be consumed) to maximise weight loss and prevent the yo-yo effect, the loss of muscle mass (where unwanted) and energy (within certain limits). The human organism is characterised by numerous physiological parameters, such as body temperature, the level of hormones secreted by the glands, the balance between the liquid and corpuscular part in the blood, etc., which must always be kept within a certain range for one to remain healthy. For this to happen, the body has several regulatory mechanisms at its disposal, each aimed at keeping one particular biological parameter within the normal range. This delicate balance is known in physiology as homeostasis. Now, among all the parameters that our body tries to keep more or less constant, there is also body composition. In fact, whenever something happens that threatens to break the balance, reactions take place aimed at restoring it. If, therefore, one introduces more calories than one needs, the body uses mechanisms aimed at dissipating the excess, keeping body composition constant. Conversely, if one cuts back on calorie consumption, the body reacts to economise on the remaining amount of energy (metabolic activity is reduced), again with the aim of avoiding changes in the amount of tissue deposited. These mechanisms consist of the activity of certain glands that produce hormones with the capacity, precisely, to regulate body composition.

The leptin-grelin axis

  Excess fat is stored within special biological ‘deposits’ called adipose cells or adipocytes. These cells also have an endocrine function, i.e. they have the ability to produce hormones. More specifically, they can produce a hormone called leptin. This hormone is also called the satiety hormone because when it is secreted in large quantities, and its levels in the blood are high, it causes the onset of satiety. This hormone is secreted by adipocytes when they are full of fat. This implies that when you get fat (i.e. your fat cells fill up with fat), leptin production increases. Leptin is released into the blood from the adipocytes and, via the blood stream, reaches another gland: the hypothalamus. The hypothalamus, following the action of leptin, starts producing another hormone: TRH, the thyrotropin-stimulating hormone. TRH, again via the blood, reaches a third gland: the pituitary gland. The latter produces the hormone TSH, also called thyrotropin. By the same mechanism, thyrotropin communicates with the thyroid gland, which produces two hormones: T3, also called tri-iodo-thyronine, and T4, also called tetra-iodo-thyronine or thyroxine. These two hormones are those that, more than any other, have the ability to influence cellular metabolism, accelerating it: when the amount of T3 and T4 in the blood is high, metabolic activity increases (the cells ‘work harder’) and, consequently, consume more calories. The increase in calorie consumption due to metabolic acceleration is also linked to the secondary effects of leptin. As a result of the action of this hormone, the transformation of part of T4 into its more active counterpart T3 also takes place, as well as the increased production of gonadal hormones, including testosterone, which also has a similar effect on cells as thyroid hormones. In conclusion, therefore, when one gains weight, the body causes the metabolism to speed up in order to consume more calories and restore balance. Conversely, when calories are cut and adipocytes are emptied, leptin levels in the blood are reduced. As a result, the hypothalamus no longer produces TRH, the pituitary gland does not produce TSH, the thyroid gland does not produce T3 and T4 and cell metabolism is reduced. On the other hand, when little leptin is produced, the body tends to produce its antagonist hormone ghrelin, also known as appetite hormone, in fair quantities. Ghrelin has the exact opposite function to leptin, i.e. it causes the metabolism to drop and the appetite to increase. Since leptin and ghrelin are two antagonistic hormones, as one increases, the other decreases. From what has been said, it might seem that the leptin-grelin hormone axis is such that it always keeps the amount of body fat constant and, indirectly, by influencing metabolism, that of lean mass (note that the amount of the latter is particularly sensitive to training). Well, as much as the human organism is inclined to maintain homeostasis and works through various mechanisms to do so, sometimes, as a matter of course, the balance is broken. Just as body temperature can rise (when you have a fever), just as blood sugar levels can rise (when you have diabetes), so too can body composition undergo changes.

The calorie set point

  The homeostatic mechanism for regulating body composition, as seen, alsoworks dysfunctionally for the goal of weight loss. In other words, when calories are cut in an attempt to lose weight, for all the adipocyte-hypothalamus-pituitary-thyroid-peripheral cell mechanism seen above, the metabolism drops, compensating for the calorie deficit induced by manipulating the diet. Sometimes the metabolism drops even more than necessary to compensate for the calorie deficit and one may even gain weight. This is the typical scenario of the yo-yo effect: first the calorie deficit induces an abrupt weight loss, which is followed by an equally abrupt reduction in the levels of leptin produced by the adipocytes, and there is initially a halt in the catabolic process, and then a new accumulation of mass, so much so that it exceeds the original levels. The desired weight reduction, therefore, takes place only ephemerally. As a rule, the more pronounced the reduction in calories compared to requirements, the more weight will increase due to the yo-yo effect. To prevent the yo-yo effect from occurring, it is necessary to reduce calories in relation to requirements by a minimum amount. This way, although the weight loss will be slower, the reduction in metabolism, if it takes place at all, will be delayed and unable to compensate for the induced calorie deficit. In fact, this strategy is likely to cause a reduction in adipocyte size over a longer or shorter period of time (depending on the duration of the history of overweight). And since the increase in lipogenic activity produced by them is proportional to their size, a reduction in these will favour a change in body composition towards which homeostasis will tend in a leaner direction. There is therefore an amount of calories below which one must not fall, on pain of the yo-yo effect. Well, this limit is called the calorie set point. The calorie set point differs from person to person: for someone it is just 300kcal less than they need, for someone else it can be as low as minus 1000kcal. To find it, it is necessary to experiment: my advice is to start by cutting calories by 10% of requirements. For example, if your daily requirement is 2500kcal, you reduce your calorie intake by 250kcal, thus taking on 2250kcal. If you notice too abrupt a weight reduction (you need to check your body composition every week) of more than a kilo per week, you should increase your calorie intake a little, but still remain below the requirement. If, on the contrary, the weight loss is insignificant, a larger calorie cut can be made. To specify what is meant by insignificant weight loss, the significance of the weight loss is a function of the speed with which weight is usually shed and is subjective. If one is inexperienced, a loss of 100 or 200 grams per week, especially taking into account the possible measurement errors of inaccurate instruments, can be considered, as a maximum value, as an insignificant loss that justifies a more drastic calorie cut. However, even if you follow this rule, you cannot lose weight forever. The day will come, however, when the process will come to a halt. On that day, you will have to reduce your calories by a further 5-10% calculated from your basal requirement. Returning to the example above, if the basal requirement is 2500kcal, and if after eating 2250kcal for 4 weeks and continuing to lose weight, a blockage occurs, then a further cut in calories to 2000-2125 calories per day will be made. If another blockage occurs after a few weeks, you can proceed with a further cut, but the recommendation to never go below 70% of requirements is particularly important, especially for very committed athletes (for example, for a 2500kcal requirement, never go below 1750kcal per day). In fact, the greater the calorie cut compared to basal requirements, the greater the risk of injury and the lower the quality of recovery. If a further calorie cut does not lead to a restart of the weight loss process, then it means that it is no longer possible to lose weight in this way and that a longer-term strategy is required. One way of delaying the blockage is to include every 2 to 8 weeks of a low-calorie diet one or two weeks of isocaloric (i.e. a diet in which you take in ‘exactly’ the amount of calories you need) or more moderate low-calorie diets in which you do not try to lose weight. Once the process is over, either because you have reached your intended weight, or because you are no longer able to reduce mass, you must gradually return to the isocaloric regime, increasing your daily (average) calories from week to week by 10-15% of what you need. Let’s look at an example of a calorie-cutting plan for a person whose requirements are 2500kcal:

1. first, calories are cut by 10 per cent of what is needed. We then set the daily intake at 2250kcal. Let us assume that we notice, from week to week, a fair (not excessive) drop in weight.
2. After 6 weeks we insert a week of an isocaloric diet to prevent a reduction in cellular metabolic activity. We then set the calorie intake at 2500 per day.
3. At the end of the isocaloric period, one starts again with the low-calorie diet of 2250kcal per day, continuing to notice the weight reduction for another 2 weeks, after which the process comes to a halt.
4. We then proceed with a further 5% calorie cut from requirements, setting the daily calorie intake at 2125kcal. We then notice a constant weight reduction for a further 6 weeks.
5. At this point we enter a week of preventing the reduction of basal metabolic rate by taking 10% fewer calories than required. We therefore set the daily calorie intake at 2250.
6. We then started again with the low-calorie diet of 2125kcal per day, noting weight loss for another two weeks, which was followed by a new crash.
7. We then cut calories by another 5 per cent to 2,000 per day. Here, then, the weight-loss process starts again.

You proceed in this way until you stop the weight loss process, either voluntarily or by force, always keeping in mind the recommendation that you should never go below 1750kcal per day (70% of basal requirement).

The metabolic reset

  As mentioned, it is not possible to lose weight forever. Sooner or later the time will come when the catabolic process will come to a halt. When this happens, it is because the cellmetabolism has shrunk so much that it prevents any further reduction in mass. In this circumstance, therefore, trying to force weight loss when the cell metabolism is such that it does not allow it will certainly be, on the one hand, a useless sacrifice and, on the other, counterproductive, because the metabolism will drop even further. What one should instead try to do is to ‘rebuild’ the metabolism by giving up losing weight for a while. Through an appropriate dietary strategy, it is possible, in fact, to get the cells to work harder, thus creating the prerequisite for a new phase of weight loss with calorie cutting (as well as with manipulation of the quality of food). The calorie-cutting phase, during which the weight loss takes place, must therefore be alternated with the ‘metabolism-building’ phase.

Building metabolism

  The metabolic building phase is a little longer than the calorie-cutting phase, but it is necessary to achieve lasting results. During this phase you have to do the exact opposite of what you do during the cutting phase. In other words, you have to gradually increase your calories, week after week. Unlike the cutting phase, however, in which calories were reduced by up to 10% at a time, in the metabolism-building phase, they must be increased much more slowly and gradually. Since, as has often been and will continue to be emphasised, every athlete is unique, there is no universally valid amount of calories to add to the daily bill. Some athletes are very sensitive to caloric increases, so much so that an extra 20kcal/day is enough to cause counterproductive effects; others can tolerate much larger increases, such as 50kcal/day. Those who do not yet know the optimal amount of calories to add will have to find this out through experiments. It is suggested to start with a weekly increase of only 10kcal/day, and then increase the extra calories by 5 units each week until you can tolerate it. In other words, you should stop the growth of the extra calorie group when you notice in your weekly bioimpedance measurements that you are accumulating excess fat. Let it be clear that it is normal and physiological to gain moderate weight during this phase. This should not be a cause for fear. It is only necessary to stop gaining extra calories when one judges the fat accumulation caused by the surplus calories to be excessive. Let us look at an example where the starting daily calories are 2500:

• 1st week: 2510kcal/day (extra calories = 10)
• Week 2: 2515kcal/day (extra calories = 10 from the previous week + 5)
• Week 3: 2525kcal/day (extra calories = 15 from previous weeks + 10)
• Week 4: 2540kcal/day (extra calories = 25 from previous weeks + 15)
• Week 5: 2560kcal/day (extra calories = 40 from previous weeks + 20)
• Etc.

Let’s assume that the body composition does not change significantly from week one to week four, while in week five there is an accumulation of fat that can be interpreted as the start of a trend towards excessive fattening. Thus the size of the group of extra daily calories to be added each week is 15. Once the size of the extra group of calories to be introduced has been identified, one must proceed with a gradual increase in daily calories by an amount equal to this. If we take the previous example, we will therefore proceed with the addition of 15kcal/day each week:

• 1st week: 2540kcal/day
• 2nd week: 2555kcal/day
• Week 3: 2570kcal/day
• Week 4: 2585kcal/day
• Etc.

Unfortunately, no matter how slowly you add calories, when they become considerably more than you actually need, you will still start to accumulate excess fat. Well, it will be necessary to stop this phase of the diet before the amount of fat accumulated exceeds the amount that you think you can dispose of in the following calorie-cutting cycle. Obviously, the prediction of how much weight you will be able to lose should be based on previous experience of slimming diets. In the absence of such experience, another way to tell when to stop (or modify) the metabolism-building phase is by the amount of weekly weight gain: body weight rarely settles on a precise value to stay there unless particular interventions are made in the diet or training regime. It is easier to notice a movement, from week to week, up and down than an average value. Now, if the calorie increase you undergo is very gradual, this trend should not change. What is likely to increase is the average value around which the weight fluctuates, but still, despite the gradual increase in calories, decreases in body weight should be observed from time to time. As long as this happens, the metabolic restoration phase can be continued. If, however, you regularly experience weight gains, perhaps even abrupt ones, then you should start thinking about discontinuing this phase and starting a cutting phase. Finally, athletes who are interested in relative strength should also keep an eye on this parameter, making sure that the accumulation of fat mass is not such that it decreases unacceptably.