Digestive capacity is specific to each athlete
Digestion relies on enzymes secreted in the mouth, the stomach, the intestines and by the pancreas. According to Alban Colot, every individual has their own digestive capacity: the quantity and efficiency of these enzymes vary with genetic background, digestive health, stress levels and the sporting context.
That is why the same nutritional strategy produces very different responses. Hence the value of assessing it, rather than applying a standard protocol.
The stomach is the cornerstone of protein digestion. When protein digestion falls short, undigested protein reaches the intestine, feeds certain bacteria and encourages a putrefactive flora. In athletes, this shows up as digestive discomfort that worsens with exercise, less available amino acids and incomplete recovery between sessions.
The framework he sets out is precise: here, an athlete is someone who trains at least four times a week, with high-intensity sessions.
The liver, the organ we talk about far too little
The liver stores hepatic glycogen and fat-soluble substances, metabolises bile, plasma proteins and urea, and clears xenobiotics, hormones and metabolic waste.
In athletes, these roles overlap. During exercise, the liver converts lactate back into glucose and maintains blood sugar, while continuing its clearance work. The result: it can start running below capacity. Not through damage, but because metabolic priority goes to the effort. This is what Alban Colot calls the athlete's hepatic sluggishness.
What drives hepatic sluggishness
- Heredity, which sets the activity of the enzymes in both detoxification phases
- The type of sport and the intensity of training
- Exposure to xenobiotics: alcohol, active and passive smoking, caffeine, environmental pollutants
- Exposure to hormones, endogenous or exogenous
- An unbalanced gut flora, which increases the release of endotoxins towards the liver
- Micronutrient status
On that last point, his example stuck: an athlete whose plate comes down to chicken, rice and broccoli, week after week, does not have enough dietary variety to cover their micronutrient status.
Another concrete case, from a consultation the day before: an athlete on 6 to 10 coffees a day, who states on the questionnaire that it is "just for the taste, not for the boost". We are beyond the recommended caffeine intake. The impact on the liver is real, even if he does not notice it in his fatigue. "Or perhaps he does not want to notice it," he adds.
Digestive problems during exercise
The phenomenon has been described since the 1980s, above all in prolonged endurance events. According to Alban Colot, it affects 30 to 50% of athletes, and now extends to disciplines such as CrossFit or Hyrox, which increase the aerobic component.
The main mechanism is the shock waves that increase intestinal movement, combined with blood flow being redistributed to the muscles and activation of the sympathetic nervous system.
Intestinal ischaemia-reperfusion
During exercise, transient intestinal hypoperfusion starves the enterocytes of oxygen. When the effort stops, the abrupt return of blood flow produces major oxidative stress. The consequences: an altered intestinal barrier, weakened tight junctions, increased permeability.
Unlike muscle, enterocytes do not develop any real protective adaptation to training. The phenomenon is amplified when training in high temperatures, since thermoregulation draws even more blood towards the skin.
As he sums it up: the athlete's problem is not a fragile gut, it is a gut under more strain than it can absorb over the long run.
The sports drink, first of all a tool for gut protection
This is the most counter-intuitive point of the webinar. Supplying the enterocytes with steady energy helps maintain part of the digestive blood flow, keeps mitochondrial reactions going, holds the ATP/ADP ratio and reduces the risk of damage to the tight junctions.
In other words: a well-tolerated sports drink is a tool for gut protection before it is ever a tool for muscular performance.
Alban Colot talks about a functional dosage: 15 to 20 g in 500 ml, not 60 g. He prefers maltodextrin, a glucose chain that goes only through the SGLT1 transporter, over an isotonic sucrose-based drink that loads the liver via fructose.
And the question every athlete asks: no, there is no significant insulin secretion during exercise. We do not store carbohydrate while exercising.
Hormesis: reading and adjusting the training load
A low to moderate stress brings about a beneficial adaptation. Excessive stress brings about harmful effects. The body is constantly trying to return to balance.
This holds for exercise, but also for fasting, cold and dietary antioxidants: at low doses they stimulate endogenous defences, at high doses around exercise they inhibit adaptation instead.
Hence the most counter-cultural warning of the webinar: faced with an athlete whose nervous system is already heavily taxed, or even exhausted, adding intermittent fasting and cold showers pushes towards maladaptation, not adaptation. Advice has to be personalised to the athlete's current status.
The questions to ask in consultation are simple:
- Is the athlete progressing on their loads, on their distances?
- Can they still hit 80% of their squat maximum even when tired?
- Across the cycles, is there real progress or regression?
The point is not to do more. It is to do just enough, at the right moment. Read this way, the practitioner's role is that of a regulator of load.
After an injury: modulate inflammation rather than shut it down
Without inflammation there is no healing. Trying to block it completely, too early, is a mistake. As he puts it on his slide: "The whole point is not to shut inflammation down, but to support it without letting it spill over."
It is the quality of the fats supplied that modulates this response. Day to day, the omega-6 to omega-3 ratio sits at around 3 to 1. In an inflammatory phase, the target would be 1 to 1, which is very hard to reach through diet alone.
One point often forgotten: gamma-linolenic acid (GLA), a precursor of PGE1, found in particular in borage oil. On erythrocyte fatty acid testing, GLA comes back low almost systematically in athletes.
Less movement does not mean fewer needs
A final marker, and probably the most actionable in rehabilitation. Tissue repair is an energy-hungry process. During the healing phase, resting metabolism can rise by 20 to 50% depending on the severity of the trauma: a factor of 1.2 for an ankle sprain or minor surgery, up to 1.5 for anterior cruciate ligament surgery.
Yes, an injured athlete should reduce their intake compared with their training period. No, they should not drop back to a sedentary intake: the risk is undereating at the exact moment the body needs materials to heal.
The question to put to the patient: is it better to carry one or two extra kilos on the scales, but heal cleanly and return to play sooner?
Questions from practitioners
What should we make of the ketogenic diet in athletes?
His position is clear: to date, there is no documented favourable adaptation to being on a ketogenic diet for performance. What he sees in practice is mostly personal choice, with athletes who keep this way of eating day to day and then switch back to normal carbohydrate intake for competition.
Among those who stay ketogenic over ultra distances, what he mostly hears are verbs of survival: "I held on", "I started to get pain", "but I made it to the end". For him, that is not an expression of performance. Sporting performance is already hard enough in itself, and adding constraints does not look optimal. He adds that better gut comfort on a ketogenic diet usually reflects insufficient training adaptation to carbohydrate intake.
How can overtraining be detected?
There is no single marker of overtraining. Without going into functional biology, two simple markers stand out: ferritin, and therefore iron stores, with a big red flag in male athletes and even more so in menstruating female athletes, and variations in white blood cells, which say something about immune fragility.
Do the lactate gels seen at the Tour de France have any value outside elite sport?
A very recent topic, discovered as the Tour began. The principle strikes him as sound, lactate being a kind of half-sugar. He places it, though, as the stone in the cherry on the cake rather than a priority, with reservations about taste tolerance, a metallic taste frequently reported, and doses of the order of five grams. Combining glucose and lactate looks to him like an interesting development for an athlete who is already well adapted.
Taking it further in consultation
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