Introduction
Newly approved and emerging anti-obesity medications (AOMs), such as semaglutide (Ozempic and Wygovy), liraglutide (saxenda) and tirzepatide (Zepbound/ Mounjaro), have changed obesity treatment dramatically in recent years by facilitating ≥5% (up to 20%) average body weight reduction. This level of weight loss (20-25%) was previously achievable only through bariatric surgery (people lose 60-75% of their excess weight – please note this is different to % of total weight lost). As obesity is now recognized as a chronic, complex, multifactoral disease, these most recent changes have prompted many more clinicians to provide more comprehensive obesity care beyond specialized treatment centres. The ‘eat less, move more’ response has become a thing of the past.
This article provides practical, evidence-based nutritional recommendations for patients undergoing AOM therapy, supporting sustained weight loss, optimal nutrition, and better health outcomes.
If you’re keen to learn more, join my webinar, “Ozempic and Dieting: All You Need to Know“, on 2nd April where I go into the necessary diet and lifestyle factors in more detail.
Understanding Obesity and the Role of AOMs
Obesity: A Chronic Disease with Serious Complications for some
Obesity is a chronic, often progressive, condition that increases the risk (does not guarantee, merely increases risk) of over 200 health complications, including:
✔ Type 2 diabetes (T2D)
✔ Cardiovascular disease (CVD)
✔ Metabolic dysfunction-associated steatohepatitis (MASH, formerly NASH and an exacerbation of nonalcoholic fatty liver disease (NAFLD))
✔ Hypertension (high blood pressure) which is a risk factor for stroke and heart disease
Other issues include metabolic syndrome, breathing problems, some cancers, gout, kidney disease, diseases of the gallbladder and pancreas, pregnancy complications, sexual dysfunction and mental health problems.
If issues like high cholesterol, high blood pressure, diabetes and metabolic syndrome develop, even modest weight reductions (≥5%) have been shown to improve these conditions. However, weight regain is common, esepcially with fad diets, as obesity involves biological, psychological, and environmental factors that make long-term weight loss challenging.
How AOMs Work
AOMs like semaglutide (Ozempic = GLP-1) and tirzepatide (Mounjaro = GLP-1 and GIP) regulate appetite and impact energy balance by targeting key hormones:
- GLP-1 (Glucagon-like peptide-1): It increases the amount of insulin that the pancreas releases in response to food. It reduces the amount of sugar/ glucose that your liver makes. These changes help control blood sugar/ glucose levels. It also reduces hunger/ appetite, increases feelings of fullness and slows digestion so that it takes longer for the body to absorb carbohydrate and sugar from food and keeps you fuller for longer.
- GIP (Glucose-dependent insulinotropic polypeptide): Enhances blood sugar management and has an impact on appetite/ satiety. It keeps a person fuller sooner and fuller for longer. This is not in Ozempic or saxenda.
Efficacy of AOMs
Liraglutide aka saxenda (GLP-1 receptor agonist)
📌 Weight loss: In one study 85% of people taking the medication lost weight. 3 in every 5 people lost 5% or more (12lb, just under a stone). 1 in every 3 achieved weight loss of more than 10% (23lb, over about 2 stone)/ About 1 in 20 lost 20% or more (47lb or over 3 stone). In a study that looked at long term weightloss, about half of people maintained their weight loss (kept it off) at 3 years.
📌 Side effects: >1 in 20 experience nausea, constipation, diarrhea. Most common adverse reactions reported are: nausea, diarrhea, constipation, vomiting, injection site issues, headache, low blood sugar, indigestion, low energy, dizziness, stomach pain, high temperatures, and gastroenteritis (vomiting and diarrhoea).
Dosage Forms and Strengths: Injection: 6 mg/mL solution in a 3 mL pre-filled pen that delivers doses of 0.6 mg, 1.2 mg, 1.8 mg, 2.4 mg or 3 mg
Semaglutide aka Ozempic (GLP-1 receptor agonist)
📌 Weight loss: Generally 5 to 15% reduction is expected across 3 months to a bit over 1 year. Although weight loss depends on starting weight, how much is taken, and for how long, as well as supporting factors e.g. dietetic input.
📌 Additional benefits: Reduced risk of heart attacks and strokes. Lowers HbA1c (average blood sugar/ glucose over 3 months thereby improving diabetes control) by 1.2 and 1.8 % over 10 to 13 months.
📌 Side effects: 1 in 10 experience nausea, constipation/ diarrhea & low blood sugar (this often depends on other meds used). It’s important to adjust dose and diet acorrdingly. A serious potential side effect is the increased risk of developing thyroid cancer. Therefore, this medication needs to be considered on a risk/ reward basis, and necessary screening needs to be considered. A red flag would be past or present problems with your pancreas or diabetic retinopathy. Please also tell your doctor if you plan to become pregnant or are pregnant.
Dosage Forms and Strengths: Ozempic (semaglutide) injection 0.25 mg, 0.5 mg, or 1 mg dose once a week (tummy, thigh or upper arm). Sometimes 2mg is offered.
WEGOVY is an injection of 2.4 mg semaglutide (i.e. Ozempic but a bigger dose).
Tirzepatide aka Mounjaro (GIP & GLP-1 receptor agonist)
📌 Weight loss: Like Ozempic, the weight loss depends on lots of factors including starting weight, the amount taken, additional support and time frame. Mounjaro leads to more weight loss. Up to 20.9% reduction over 72 weeks.
📌 Additional benefits: Lower triglycerides, improved HbA1c (up to 2.4% improvement seen)
📌 Side effects: Similar to Ozempic.
Dosage Forms and Strengths: Mounjaro is available as a 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg per 0.5 mL subcutaneous injection in a prefilled single-dose pen.
➡ New treatments under development, such as retatrutide and semaglutide–cagrilintide, may offer additional choice in the future.
Nutritional Recommendations for AOM Therapy
Patients taking AOMs experience increased feelings of fullness leadiing to lower calorie intake, making nutrient-dense food choices essential to ensure nutrient needs are met. Although the focus is initially on protein and fibre, it’s important to focus on variety of diet to hit other markers too.
Macronutrient and Fluid Guidelines
| Nutrient | General guidance | Sources | Deficiency Signs | Additional Considerations |
|---|---|---|---|---|
| Fluids | >2–3L/day | Water, herbal teas, milk, unsweetened drinks | Dizziness, dry mouth, low blood pressure | Low carb diets may further increase risk of dehydration |
| Protein | ≥ 1g/kg body weight/day (this needs to be tailored) | Lean meats, fish, dairy, eggs, beans, soya, quorn | Weakness, hair loss, loss of lean mass | Crucial for muscle preservation, especially in over 40s |
| Carbohydrates | 130g/day (but depends on size, activity levels etc…) | Whole grains, fruits, legumes | Fatigue, brain fog, bad breath | Avoid very low-carb diets, which may lead to nutrient deficiencies |
| Fats | 58g/day (depends on total energy needs) | Nuts, seeds, avocado, olive oil, fatty fish | Dry skin, hair loss, poor wound healing | Not eating enough may run risk of gall bladder issues |
| Fibre | 25-35g/day | Whole grains, vegetables, legumes, fruits | Constipation, bloating | Supports gut health and general health |
➡ Meal replacements (protein shakes, bars) can help maintain nutrient intake at times of need.
Micronutrient Considerations for Patients on AOMs
With lower food intake, deficiencies in vitamins and minerals can occur. Regular monitoring and supplementation may be necessary. Your Registered Dietitian will monitor vitamin B12, folate, iron and vitamin D through bloodwork, but will focus in on fat soluble vitamins at each appointment.
Some of the Key Micronutrients to Monitor
| Micronutrient | Sources | Deficiency Risks | Considerations |
|---|---|---|---|
| Vitamin D | Fatty fish, fortified milk, eggs, supplements | Bone and muscle weakness, poor immune function | Consider supplementation |
| Vitamin B12 | Meat, fish, dairy, eggs | Fatigue, psychological function | Risk increases with metformin use |
| Iron | Red meat, beans, fortified grains | Fatigue, dizziness | Pair plant sources of iron with vitamin C-rich foods for better absorption |
| Calcium | Dairy, kale, fortified plant milk | Bone loss | Requirements can increase with age in women |
| Magnesium | Nuts, seeds, green veg | Blood pressure changes | Magneisum oxide supplements can have a laxative effect |
➡ Complete multivitamin supplementation is often recommended for AOM patients to prevent deficiencies. However, it’s important to avoid one with iron if you have haemachromotosis.
Addressing Common Challenges with AOMs
1. Gastrointestinal Side Effects (Nausea, Diarrhea, Constipation)
✔ Eat smaller meals
✔ Consider lowering/ reducing your dose of medication (talk to a member of your team eg doctor, dietitian, pharmacist
✔ Increase fibre and fluids for constipation
✔ If severe, consider slower dose escalation or maintaining
2. Excessive Weight Loss
✔ Monitor weight as fast, excessive weight loss isn’t the goal in most cases.
✔ Increase protein and calorie intake if needed
✔ Adjust AOM dosage if weight loss becomes problematic
3. Emotional & Social Adjustments
✔ Some patients struggle with body image changes or social interactions during and after weight loss. This is important to discuss with your team.
✔ Support groups or therapy will often help.
Who Should Be Monitored Closely?
✔ Older Adults: Higher risk of muscle loss, bone loss, dehydration, and deficiency
✔ Bariatric Surgery Patients: Increased risk of micronutrient deficiencies
✔ Patients with Chronic Diseases: Those on diuretics, metformin, or proton pump inhibitors need nutrient monitoring
✔ Individuals with Eating Disorders: AOMs are not recommended for those with anorexia or bulimia.
The Future of AOMs and Obesity Treatment
Recent breakthroughs in AOM therapy have changed obesity treatment, providing substantial weight loss with less invasive interventions (not surgery). However, nutritional management remains crucial to:
✅ Preserve muscle mass (alongside strength training and lifestyle changes)
✅ Prevent micronutrient deficiencies
✅ To help make weight loss as healthy and safe as possible
📌 Personalized, evidence-based nutritional guidance is essential for patients using AOMs.
👉 Looking for expert nutrition support while on AOM therapy? Book a consultation with our dietitians today.
Important
This article does not dive into how these injections are being abused, or how they are getting into the wrong hands leading to serious health risks. This article aims to inform, not promote.
