Extreme diets and sport
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Are they good for performance?
Lately there has been a lot of talk about the carnivore diet. Have you tried it? Does it work? Have you noticed any side effects? Let’s look into the subject more closely, reflecting on whether very restrictive and rigid eating regimes are useful in general, and in sport in particular.
The carnivore diet is very simple. It involves eating only foods of animal origin, such as meat, fish and eggs, and cutting out plant foods of all kinds, such as fruit, vegetables, cereals, nuts and pulses. Dairy products may be eaten, since they are clearly of animal origin, but excluding all dairy products with a high lactose concentration, such as milk and yoghurt, in favour of mature cheeses and butter.
Right, but how much should you eat at each meal? How should meals be spread across the day?
It is all very simple: just follow your sense of fullness and eat the permitted foods according to how you feel, without even worrying about rotating or repeating foods.
Drinks are a separate chapter. No drinks other than water or broth. There is no way round it.
But is all this good for you? It is hard to give a clear-cut interpretation, especially when there is a lack of specific scientific studies describing the long-term effects of a given eating plan on a sufficiently large number of participants. Any considerations are based on scientific evidence relating to individual aspects.
Such an unbalanced diet, weighted heavily towards protein, could be useful for weight control, provided that reasonable portions are eaten. A higher protein intake is in itself a good starting point for considering an eating plan aimed at weight loss effective, given the greater thermogenic effect resulting from the more complex digestion of peptide bonds compared with fats and carbohydrates, as well as the corresponding increase in the feeling of fullness after a meal. As for the possibility of inducing ketosis, which is so useful for increasing the use of lipid reserves drawn from a person’s fat mass, we feel we can rule it out; in particular situations of need, the body can in fact convert certain amino acids into glycogen, preventing the formation of ketone bodies. For this reason, ketosis is achieved by keeping protein intake under control as well, not just carbohydrate intake.
In terms of performance and well-being, athletes would certainly gain some advantages from foods like these, but they would also clearly need to adapt to the new regime, especially in certain sports.
An athlete who does endurance sports, for example, will inevitably have to change their habits and get through an initial, unavoidable period of biochemical adaptation, shifting their metabolic balance towards burning fats rather than carbohydrates, even at the same level of effort. This period may be longer or shorter, generally ranging from a few days to a month. Another difficulty could be the availability of mineral salts and vitamins, especially when the amount of fluid lost through sweat becomes significant.
Can we be sure of replacing all the required amounts, especially over the long term, without risking fluid and electrolyte imbalances or deficiencies, without eating any fruit or vegetables at all? Unfortunately there are no definite answers to these doubts.
These adaptations would certainly be gentler in the case of strength sports, explosive and contact sports and/or high-intensity, short-duration sports, making the choice to follow this regime much easier and perhaps even useful for maintaining muscle tissue function.
In absolute terms, we wonder how it is possible to benefit from such an unusual eating plan, especially without a specialist nutritionist following the patient along the way, without overdoing the quantities of freely allowed food and instead sticking to one’s sense of fullness and personal common sense.
The risks are undoubtedly just around the corner. Especially in people genetically predisposed to certain diseases, such an imbalance of macro- and micronutrients would not be advisable, particularly if continued for long periods. Kidney and liver function could be most at risk, along with an increase in cardiovascular risk factors, generalised inflammation and higher concentrations of free radicals.
In short, we are looking at an excess that could carry more risks than benefits. It would certainly not be a bad thing to include some “alternative” days in our eating pattern, perhaps richer in some foods than others, but the goal of maintaining a constant balance, especially over the medium to long term, should in our view remain firmly in the minds of both the individual and the nutritionist.
Lately there has been a lot of talk about the carnivore diet. Have you tried it? Does it work? Have you noticed any side effects? Let’s look into the subject more closely, reflecting on whether very restrictive and rigid eating regimes are useful in general, and in sport in particular.
The carnivore diet is very simple. It involves eating only foods of animal origin, such as meat, fish and eggs, and cutting out plant foods of all kinds, such as fruit, vegetables, cereals, nuts and pulses. Dairy products may be eaten, since they are clearly of animal origin, but excluding all dairy products with a high lactose concentration, such as milk and yoghurt, in favour of mature cheeses and butter.
Right, but how much should you eat at each meal? How should meals be spread across the day?
It is all very simple: just follow your sense of fullness and eat the permitted foods according to how you feel, without even worrying about rotating or repeating foods.
Drinks are a separate chapter. No drinks other than water or broth. There is no way round it.
But is all this good for you? It is hard to give a clear-cut interpretation, especially when there is a lack of specific scientific studies describing the long-term effects of a given eating plan on a sufficiently large number of participants. Any considerations are based on scientific evidence relating to individual aspects.
Such an unbalanced diet, weighted heavily towards protein, could be useful for weight control, provided that reasonable portions are eaten. A higher protein intake is in itself a good starting point for considering an eating plan aimed at weight loss effective, given the greater thermogenic effect resulting from the more complex digestion of peptide bonds compared with fats and carbohydrates, as well as the corresponding increase in the feeling of fullness after a meal. As for the possibility of inducing ketosis, which is so useful for increasing the use of lipid reserves drawn from a person’s fat mass, we feel we can rule it out; in particular situations of need, the body can in fact convert certain amino acids into glycogen, preventing the formation of ketone bodies. For this reason, ketosis is achieved by keeping protein intake under control as well, not just carbohydrate intake.
In terms of performance and well-being, athletes would certainly gain some advantages from foods like these, but they would also clearly need to adapt to the new regime, especially in certain sports.
An athlete who does endurance sports, for example, will inevitably have to change their habits and get through an initial, unavoidable period of biochemical adaptation, shifting their metabolic balance towards burning fats rather than carbohydrates, even at the same level of effort. This period may be longer or shorter, generally ranging from a few days to a month. Another difficulty could be the availability of mineral salts and vitamins, especially when the amount of fluid lost through sweat becomes significant.
Can we be sure of replacing all the required amounts, especially over the long term, without risking fluid and electrolyte imbalances or deficiencies, without eating any fruit or vegetables at all? Unfortunately there are no definite answers to these doubts.
These adaptations would certainly be gentler in the case of strength sports, explosive and contact sports and/or high-intensity, short-duration sports, making the choice to follow this regime much easier and perhaps even useful for maintaining muscle tissue function.
In absolute terms, we wonder how it is possible to benefit from such an unusual eating plan, especially without a specialist nutritionist following the patient along the way, without overdoing the quantities of freely allowed food and instead sticking to one’s sense of fullness and personal common sense.
The risks are undoubtedly just around the corner. Especially in people genetically predisposed to certain diseases, such an imbalance of macro- and micronutrients would not be advisable, particularly if continued for long periods. Kidney and liver function could be most at risk, along with an increase in cardiovascular risk factors, generalised inflammation and higher concentrations of free radicals.
In short, we are looking at an excess that could carry more risks than benefits. It would certainly not be a bad thing to include some “alternative” days in our eating pattern, perhaps richer in some foods than others, but the goal of maintaining a constant balance, especially over the medium to long term, should in our view remain firmly in the minds of both the individual and the nutritionist.