For a variety of reasons, foods, meals and diets high in fibre and protein are being promoted as nutritional must haves at present. It may be due to decades long campaigns to demonise fats and carbohydrates, leading to consumers, food industry and their pundits focusing on what’s left of the macronutrients. Alternatively, it may be due to the increasing popularity and use of the latest weight loss marvels: the incretins.What are incretins?Incretins are kinds of hormones composed of peptides (small proteins) that are secreted in the intestines after consuming foods or nutrients. They stimulate insulin secretion by the pancreas and decrease the rate of emptying/amount of acid produced by the stomach, decreasing appetite and food intake, amongst other things.Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the best known incretin hormones and are what are found in popular diabetes and weight-loss medications like liraglutide (Mounjaro/Saxenda) and (Ozempic/Wegovy).How effective are they?As many people are aware, the latest versions of incretin medications are very effective at lowering HbA1c (1-1.5% point reductions) and body weight (15-25% of initial weight) in the short to medium term (2-3 years) in clinical trials.Like most medications, effects start to reverse as soon as the therapy is ceased, however. Clinical trials indicate that around 60% of weight lost is regained 12 months after ceasing therapy and it’s estimated that this plateaus to around 75% regain in the longer term, based on the best available evidence. The solution may be to continue taking them long term, but at this point in time, we do not know what the consequences of doing that are.What are the side effects?Depending on the kinds of incretin therapy and the dose, side effects are common, especially when starting treatment or when the dose is increased. The most common shorter-term side effects perhaps unsurprisingly are increased risk of gastrointestinal events, including nausea, vomiting, diarrhea, dyspepsia (indigestion), and constipation. Nausea and vomiting are more common with prolonged therapy.Less commonly talked about are the potential negative impact on people’s nutritional status. People that are overweight or obese frequently have biochemical evidence of deficiencies of vitamin D, B12, folate, thiamine, iron, and zinc. Inadequate intakes of calcium, magnesium, and vitamins A, E, and C have also been reported.Additionally, overweight/obesity can coexist with sarcopenia, a reduction in skeletal muscle mass and strength, most often associated with aging. People with diabetes have a higher prevalence of sarcopenia. Incretins cause loss of lean mass (∼10% or ∼6 kg), comparable to a decade or more of aging.Eat more fibre and protein?Other than fad diet exhaustion, the increasingly common use of incretin therapies in certain parts of the world may be driving the promotion of foods, meals and diets high in fibre and protein.High fibre diets may offset some of the more common side effects of these medications like constipation and diarrhea (e.g., psyllium). Consuming optimal amounts of fluids and keeping physically active are also important factors.Higher protein diets may help decrease the loss of lean body mass provided it’s high quality, and energy (kilojoule/Calorie) restriction is not too severe. Regular physical activity will also help reduce muscle wasting.For those of us not using these medications, we most likely do need to increase our fibre intake as most of us do not consume the recommended 25g or more per day. However, most of us in the “Western” world do eat enough protein, but many of us can improve the quality.
Dr Alan Barclay, PhD, is an Accredited Practicing Dietitian, nutritionist and chef with a particular interest in carbohydrates, diabetes and food law. He is author of Reversing Diabetes, and co-author of 40+ scientific publications, The Good Carbs Cookbook (Murdoch Books), Managing Type 2 Diabetes (Hachette Australia) and The Ultimate Guide to Sugars and Sweeteners (The Experiment Publishing).
