Supporting, not judging the prescription
Dr Anne Lucas sets the frame from the outset: the point is not to debate the value of prescribing GLP-1 and GIP agonists, which have become unavoidable, but to act as a health professional practising micronutrition and functional medicine. These patients will take their treatment either way. The question is how to help them get the benefits, tolerate the side effects better and achieve results that last.
The stakes are all the higher because obesity is now defined as a chronic disease, and these molecules are designed as long-term treatment. For her, this is exactly where the functional approach makes sense: seeing these agonists as a window of opportunity to put the right nutritional, micronutritional and lifestyle strategies in place, working on the root causes of the metabolic disorder.
A reminder she repeats throughout her talk: doses, titration and tapering are for the prescribing doctor to decide, within the summary of product characteristics.
GLP-1 and GIP: what physiology teaches us
Unlike some drug classes of the past, GLP-1 and GIP exist in the body. They are two incretin hormones secreted by the gut in response to food intake: GLP-1 by L cells, GIP by K cells. Their physiological concentration is in the picomolar range and their half-life is no more than a few minutes.
Dr Anne Lucas highlights a clinical point: in people with obesity, and even more in people with type 2 diabetes, GLP-1 secretion in response to carbohydrates is sharply reduced, while it is preserved in response to fats. The agonists are synthetic molecules that act on the same receptors at milligram-range doses, with a half-life of several days, hence weekly administration.
Insulin sparing rather than a secretagogue effect
This is the notion she asks practitioners to remember. GLP-1 increases insulin secretion, but in a glucose-dependent way: without a rise in blood glucose, there is no amplification. Yet all the other actions of these treatments lower blood glucose upstream: less hunger and fewer food cravings, more satiety, slower gastric emptying. The result: less need for insulin. Dr Anne Lucas speaks of insulin sparing rather than the secretagogue effect sometimes wrongly attributed to them.
Losing weight or optimising body composition?
The weight results are unprecedented for a medicine: close to 21% average weight loss over 72 weeks with tirzepatide, against around 3% on placebo. But for Dr Anne Lucas, the goal of functional support is not to lose weight. It is to optimise body composition.
According to studies, loss of non-fat mass can reach 40% of the weight lost, a large part of it muscle mass. On top of that comes a risk of bone loss, especially in perimenopausal or postmenopausal women. Hence her recommendation: a DEXA scan before treatment, then at six months and at one year, to track how body composition actually evolves. Anne-Catherine Dumortier adds that the tool is also very educational for patients.
Rebuilding the plate: protein first
A significant share of patients on agonists simply eat less of what they ate before. The calorie deficit takes no effort since they are no longer hungry. But eating smaller amounts of the same foods does not restore metabolic health. The aim of support is to rebuild a healthy eating pattern so that results last if treatment stops.
Structuring meals
Dr Anne Lucas suggests three structured meals with no snacking, which is easy to set up when hunger is reduced. She pairs this with early time-restricted eating: a last meal taken as early as possible, an overnight fasting window of at least 12 hours, and hydration between meals.
Protein at the centre of every plate
This is her first recommendation for any patient on a GLP-1 agonist: make good-quality dietary protein the priority. Because food volume falls, a sufficient amount of protein and micronutrients has to be concentrated into small portions. Her guidelines:
- Per meal: at least 25 to 30 g of protein and 2.5 g of leucine, the threshold that activates muscle protein synthesis.
- Per day: at least 1.2 g per kilo of body weight, and in practice she aims for 1.5 g. When the effect of the treatment wanes and cravings return, she sometimes goes up to 2 g.
- Personalise: needs are not the same for a woman who is 1.50 m tall and a man who is 1.90 m, nor with different levels of physical activity.
Meat, poultry, offal, eggs, dairy: she favours animal protein for its complete essential amino acid profile and its digestibility. In the Q&A, she mentions protein powders made from pea or pumpkin seed, tofu and tempeh for vegetarian patients. She also points out that, in the absence of kidney disease, studies on the safety of protein intake show a good margin, up to 3 g per kilo per day.
Carbohydrates and fats: a nuanced view
In insulin-resistant patients, carbohydrates should not be the priority on the plate. According to Dr Anne Lucas, optimising protein intake improves hunger and satiety signals so much that reducing refined carbohydrates often follows naturally. She prefers to reason in net carbohydrates rather than glycaemic index, with thresholds adapted to each patient's degree of insulin resistance.
As for fats, she encourages practitioners to stop fearing them: many of these patients have restricted fat all their lives. Good-quality fats at every meal, in small amounts depending on tolerance, contribute to satiety, better post-meal blood glucose and the stimulation of bile secretion. What she rules out: industrial trans fats and poor-quality seed oils.
Preserving muscle mass: the plate is not enough
Muscle protein synthesis responds to two signals: a nutritional signal, protein and leucine intake, and a mechanical signal. Dr Anne Lucas insists: every patient on a GLP-1 agonist should be advised to do resistance training, meaning progressive strength work. Patients with excess weight tend to favour cardio and endurance; that is not the activity that optimises body composition.
She adds a simple tip for blood glucose: walking for 10 to 20 minutes after each meal helps smooth post-meal glucose variations.
Micronutrients: a higher risk of deficiencies
With a few hundred calories a day and foods whose micronutrient density is already declining, these patients are particularly exposed to deficiencies. Deficiencies in iron, vitamin B12, iodine and vitamin D are found in these patients. The aim is not to wait for a deficiency, but to bring each status towards optimal health values rather than statistical reference ranges.
She gives the example of ferritin in a premenopausal woman: between 15 and 150 depending on the lab, but an optimal value around 75. In practice, she suggests screening fat-soluble vitamins, B vitamins, selenium, zinc and iodine through functional lab testing, starting with a multivitamin while waiting for the results, then adjusting with single-nutrient formulas.
Digestive issues and titration
Nausea, reflux, constipation or diarrhoea are the most common side effects. She recalls the value of slow titration, to be discussed with the prescribing doctor, and a practical tip: since side effects peak one to three days after the injection, doing it on a Thursday often means getting through that peak over the weekend.
When the root cause is psycho-emotional
In some patients, the imbalance in energy balance is not primarily metabolic. A conflicted relationship with food, emotional eating, binge-eating episodes, cognitive restraint: in these situations, GLP-1 agonists are a valuable help, because they quieten cravings and "food noise". For Dr Anne Lucas, this is the moment to work on the relationship with food, alone or with psychologists and dietitians trained in the psychonutritional approach, so that the patient has tools when the cravings come back.
A clinical case: 60 kg lost, 8 kg regained in three months
Dr Anne Lucas closed with a case she had seen that very day. A man 1.80 m tall, who had reached 140 kg, with fatty liver disease and an insulin level of 25 without being diabetic, took tirzepatide for a year. He lost almost 60 kg without difficulty, and his insulin level fell from 25 to 5. He stopped after a year: the cost of treatment, side effects, the return of sugar cravings. Three months later, he had regained 8 kg.
During the year of treatment, he had simply eaten less of the same things, lots of ultra-processed foods and carbohydrates, and done only endurance exercise. His DEXA showed almost 30% of muscle mass lost. The treatment worked; what was missing was the support. The work started with him: prioritise protein, limit carbohydrates and introduce strength training.
Energetica Natura's micronutritional approach
Anne-Catherine Dumortier, doctor of pharmacy and naturopath, then presented four areas of micronutritional support for these patients, stressing that they replace neither work on the plate, nor physical activity, nor psycho-emotional support:
- Supporting muscle mass: whey protein isolate rich in leucine, creatine monohydrate and collagen peptides.
- Limiting deficiencies: electrolytes, multivitamins, B vitamins in active form, fat-soluble vitamins and omega-3, before a tailored adjustment guided by lab tests.
- Improving digestive comfort: support for gastrointestinal motility, digestive enzymes, support for the intestinal lining and fibre.
- Preparing for after treatment: supporting insulin sensitivity, energy metabolism, the management of sugar cravings and sleep quality.
She insists on one point: these protocols provide guidelines, to be personalised for each patient. All four protocols are on the Simplycure Academy, with products and dosages: find them on the webinar page, ready to recommend to your patients or adjust to their situation.
Watch the webinar
The full replay (in French) is available below, with chapters. The last part answers practitioners' questions: protein for vegetarians and lactose intolerance, red meat, eggs, kidney function, spreading protein across the day, DEXA, the micronutrient density of foods and the place of carbohydrates. The replay is also on the Simplycure Academy, with the products presented and the four protocols.
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