• Healthy eating is important for all of the Irish population, regardless of body size, weight or health status. The Irish healthy eating guidelines can be used as a resource for nutrition- and food-related guidance for the general population.
• Use evidence-based nutrition resources to give your patients nutrition advice that aligns with their values, preferences, and social determinants of health (Figure 1).
• There is no one-size-fits-all eating pattern for obesity management. Adults living with obesity may consider various nutrition intervention options that are clientcentred and flexible. Evidence suggests this approach will better facilitate long-term adherence (Table 1, Figure 2). Consideration should be given to flexibly synergising beneficial elements of various nutrition approaches with a focus on health outcomes.
• Nutrition interventions for obesity management should incorporate the concept of “best weight”, focus on achieving health outcomes, meeting individualised nutrition requirements and quality of life improvements, not just weight changes. Table 2 outlines health-related outcomes to support patients/ clients in obesity management.
• Nutrition interventions for obesity management should emphasise individualised eating patterns, food quality and a healthy relationship with food. Interventions that help improve awareness of hunger and satiety, lower food cravings and reduce reward-driven eating and may be important.
• Caloric restriction can achieve short-term reductions in weight (i.e., < 12 months) but has not shown to be sustainable long term (i.e., > 12 months). Caloric restriction may affect neurobiological pathways that control appetite, hunger, cravings, and body-weight regulation that may result in increased food intake and weight gain.
• People living with obesity are at increased risk for micronutrient deficiencies including but not limited to vitamin D, vitamin B12 and iron deficiencies. Restrictive eating patterns and obesity treatments (e.g., medications, bariatric surgery) may also result in micronutrient deficiencies and malnutrition. Assessment including biochemical values can help inform recommendations for food intake, vitamin/mineral supplements, and possible drug-nutrient interactions.
• Collaborative care with a dietitian registered with CORU, the authority responsible for the regulation of health and healthcare professionals in Ireland, who has experience in obesity management and medical nutrition therapy is recommended. Registered dietitians (RDs) can support people living with obesity who also have other chronic diseases, malnutrition, food insecurity or disordered patterns of eating. The representative body for Irish RDs is the Irish Nutrition and Dietetic Institute (www.indi.ie).
• Future research should use nutrition-related outcomes and health behaviours in addition to weight and body-composition outcomes. Characterisation of population sample collections should use the updated definition of obesity as “a complex chronic disease, characterised by abnormal or excessive body fat (adiposity), that impairs health,” rather than body mass index (BMI) exclusively. Qualitative data is needed to better understand the lived experience of people with obesity and how that relates to nutrition and eating behaviours.

1. We suggest that nutrition recommendations for adults of all body sizes should be personalised to meet individual values, preferences and treatment goals to support a dietary approach that is safe, effective, nutritionally adequate, culturally acceptable, affordable and enjoyable for long-term adherence (Level 4, Grade D)¹
2. Adults living with obesity should receive individualised medical nutrition therapy provided by a dietitian registered with CORU, the authority responsible for the regulation of health and healthcare professionals in Ireland (when available) to improve health outcomes, including weight (body weight, body mass index), waist circumference (WC), glycaemia, lipids and blood pressure (BP) (Level 1a, Grade A)².
3. Adults living with obesity and impaired glucose tolerance (pre-diabetes) or type 2 diabetes mellitus (T2DM) may receive medical nutrition therapy provided by a CORU registered dietitian (when available) to improve glycaemia and BP and reduce body weight and WC (Level 2a, Grade B)^3,4.
4. Adults living with obesity can consider any of the multiple medical nutrition therapies to improve health-related outcomes, choosing the dietary patterns and food-based approaches that support their best long-term adherence:

a. Calorie-restricted dietary patterns emphasising variable macronutrient distribution ranges (lower, moderate, or higher carbohydrate with variable proportions of protein and fat) to achieve similar body weight reduction over six to 12 months (Level 2a, Grade B)⁵.

b. Mediterranean dietary pattern to improve glycaemia, high density lipoprotein cholesterol (HDL-C) and triglycerides (Level 2b, Grade C)⁶; reduce cardiovascular events (Level 2b, Grade C)⁷; reduce risk of T2DM (Level 2b, Grade C)^8,9 and increase reversion of metabolic syndrome (Level 2b, Grade C)¹⁰ with little effect on body weight and WC (Level 2b, Grade C)¹¹.

c. Vegetarian dietary pattern to improve glycaemia, established blood lipid targets including low density lipoprotein cholesterol (LDL-C), and reduce body weight, (Level 2a, Grade B)¹², risk of T2DM (Level 3, Grade C)¹³ and coronary heart disease incidence and mortality (Level 3, Grade C)¹⁴.

d. Portfolio dietary pattern to improve established blood lipid targets including LDL-C, apolipoprotein B (apo B) and non-HDL-C (Level 1a, Grade B)¹⁵, C-reactive protein (CRP), BP and estimated 10-year coronary heart disease risk (Level 2a, Grade B)¹⁶.

e. Low-glycaemic index dietary pattern to reduce body weight (Level 2a, Grade B)16, glycemia (Level 2a, Grade B)17, established blood lipid targets including LDL-C (Level 2a, Grade B)18, and BP (Level 2a, Grade B)19, and the risk of T2DM (Level 3, Grade C) 20 and coronary heart disease (Level 3, Grade C)21.

f. Dietary Approaches to Stop Hypertension (DASH) dietary pattern to improve BP (Level 2a, Grade B)22, established lipid targets including LDL-C (Level 2a, Grade B)22, CRP (Level 2b, Grade B)23, glycaemia (Level 2a, Grade B)22, reduce the risk of T2DM, cardiovascular disease (CVD), coronary heart disease and stroke (Level 3, Grade C)22, and to reduce body weight and WC (Level 1a, Grade B)24.

g. Nordic dietary pattern to improve BP (Level 2b, Grade B)25 and established blood lipid targets, including LDL-C, apo B, (Level 2a, Grade B)26, non-HDL-C (Level 2a, Grade B)27, reduce the risk of cardiovascular and all-cause mortality (Level 3, Grade C)28, and reduce body weight (Level 2a, Grade B)29 and body weight regain (Level 2b, Grade B)25.

h. Partial meal replacements (replacing one to two meals/day as part of a calorie-restricted intervention) to reduce WC, BP, body weight and improve glycaemia (Level 1a, Grade B)³⁰.

i. Intermittent or continuous calorie restriction achieved similar short-term body weight reduction (Level 2a, Grade B)³¹.

j. Pulses (i.e., beans, peas, chickpeas, lentils) improve glycaemia (Level 2, Grade B)³², established lipid targets including LDL-C (Level 2, Grade B)³³, systolic BP (Level 2, Grade C)³⁴, reduce the risk of coronary heart disease (Level 3, Grade C)³⁵ and to improve body weight (Level 2,Grade B)³⁶.

k. Vegetables and fruit to improve diastolic BP (Level 2, Grade B)³⁷, glycemia (Level 2, Grade B)³⁸, reduce the risk of type 2 diabetes (Level 3, Grade C)³⁹ and cardiovascular mortality (Level 3, Grade C)⁴⁰.

l. Nuts to improve glycaemia (Level 2, Grade B)⁴¹, established lipid targets including LDL-C (Level 3, Grade C)⁴² and reduce the risk of CVD (Level 3,Grade C)⁴³.

m. Whole grains (especially from oats and barley) to improve established lipid targets including total cholesterol and LDL-C (Level 2, Grade B)⁴⁴.

n. Dairy foods to reduce the risk of type 2 diabetes and CVD (Level 3, Grade C)³⁹ and to reduce body weight, WC, body fat and increase lean mass in calorie-restricted diets but not in unrestricted diets (Level 3, Grade C)⁴⁵.

5. Adults living with obesity and impaired glucose tolerance (pre-diabetes) should consider intensive interventions that target a 5% – 7% weight loss to improve glycaemia, BP and blood lipid targets (Level 1a, Grade A)46, reduce the incidence of T2DM (Level 1a, Grade A)47, microvascular complications (retinopathy, nephropathy and neuropathy) (Level 1a Grade B)48 and cardiovascular and all-cause mortality (Level 1a, Grade B)48.
6. Adults living with obesity and T2DM should consider intensive interventions that target a 7% – 15% weight loss to increase the remission of T2DM (Level 1a, Grade A)⁴⁹ and reduce the incidence of nephropathy (Level 1a, Grade A)⁵⁰, obstructive sleep apnoea (Level 1a, Grade A)⁵¹ and depression (Level 1a, Grade A)⁵².
7. We recommend non-restrictive approaches to improve quality of life, psychological outcomes (general wellbeing, body image perceptions), cardiovascular outcomes, body weight, physical activity, cognitive restraint and eating behaviours (Level 3, Grade C)⁵³.

• Nutrition is important for everyone, regardless of body size or health. Your health is not a number on a scale. If you’re thinking about making a change to the way you eat, choose eating goals that improve overall nutrition and health (medical, functional, emotional health) (Table 2).
• There is no one-size-fits-all healthy eating pattern. Choose an eating pattern that supports your best health and one that can be maintained over time, rather than a short-term “diet”. Talk to a healthcare professional (HCP) to discuss the advantages and disadvantages of different eating patterns to help achieve your health-related goals. How you eat is as important as what and how much you eat. Practice eating mindfully and build a healthy relationship with food.
• Severely restricting the amount you eat may mean you miss out on important nutrients for health and may cause changes to your body that lead to weight regain over time. If you’re thinking about these approaches, you should discuss this with a HCP.
• See a dietitian registered with CORU, the authority responsible for the regulation of health and healthcare professionals in Ireland, for an individualised approach and ongoing support for your nutrition and health-related needs. The representative body for Irish registered dietitians is the Irish Nutrition and Dietetic Institute (www.indi.ie).