If you’ve ever wondered why some people feel full after a small meal, why others constantly crave sweets, or why weight loss feels harder for you than it “should,” your genetics may hold important clues.

A personalised nutrigenetic functional test can help identify metabolic tendencies and guide a tailored nutrition plan based on your unique biology. With this information, you can shape a nutrition plan that works with your biology instead of against it.

How DNA Is Measured in Genetic Testing

Genetic tests don’t read your whole genome. Instead, they scan specific locations called SNPs (single nucleotide polymorphisms). Here’s how it works:

• A saliva or cheek-swab sample is collected.

• Your DNA is broken into small fragments.

• A microarray chip checks thousands of SNP sites.

• At each site, the machine identifies which two bases you carry (A, T, C or G).

• If the SNP changes a protein, the result is also shown as amino acids (e.g., Thr/Ile).

• For some older SNPs, historical labels (A1/A2) are used.

The final report tells you which versions of each SNP you have. SNPs can influence how enzymes work, how receptors respond to hormones and how effectively your body performs metabolic tasks. Some SNPs change the shape of a protein (shown as amino acids like Pro, Ala, Gly). Others simply affect regulation (shown as A/T/C/G). A few still use historical names like A1/A2. Each SNP below affects a different aspect of metabolism or appetite regulation.

ADRB2 (Adrenergic Beta-2 Receptor)— How Efficiently You Mobilise Stored Energy

SNPs: rs1042713 (Arg16Gly), rs1042714 (Gln27Glu)

ADRB2 affects how your fat cells respond to adrenaline — which determines how easily you burn stored fat, how quickly you mobilise glucose and how metabolically “flexible” you are.

rs1042713 (Arg16Gly)

• AA (Arg/Arg): slower fat mobilisation; may feel sluggish with high carb intake

• AG (Arg/Gly): moderate response

• GG (Gly/Gly): sustained fat oxidation; better carb tolerance

rs1042714 (Gln27Glu)

• CC (Gln/Gln): receptors desensitise quickly

• CG (Gln/Glu): average response

• GG (Glu/Glu): stable receptors; improved metabolic flexibility

What this means for you

If your receptors down-regulate easily, high-sugar foods may lead to energy crashes and easier fat gain. You may feel your best with steady meals built around lean protein, fibre and controlled carbohydrates.

MC4R (Melanocortin 4 Receptor) — The Gene That Sets Your Appetite “Volume”

SNP: rs17782313

MC4R influences your natural hunger signals and how satisfied you feel after eating.

Genotypes

• TT: typical satiety

• TC: slightly increased hunger

• CC: reduced fullness → large portions, snacking, emotional eating

What this means

If you carry the C allele, hunger is not “your fault” — your brain’s satiety signals simply reset more slowly. You may thrive with structured eating, high-protein breakfasts and high-volume meals that stretch the stomach without adding calories.

PPARG (Peroxisome Proliferator-Activated Receptor Gamma) — Your Insulin-Sensitivity Master Switch

SNP: rs1805192 (Pro12Ala)

PPARG is essential for glucose metabolism and how efficiently your body stores and releases energy.

Genotypes

• CC (Pro/Pro): higher risk of insulin resistance

• CG (Pro/Ala): improved insulin response

• GG (Ala/Ala): most insulin-sensitive profile

What this means

If you are Pro/Pro, your body may struggle with large carb-heavy meals. A Mediterranean dietary pattern (olive oil, legumes, vegetables, fish) is especially beneficial for this genotype.

AGER / RAGE (Advanced Glycation Endproduct Receptor) — Glycation, Inflammation and Metabolic Ageing

SNP: rs2070600 (Gly82Ser)

AGER controls how strongly your cells react to AGEs — inflammatory compounds produced from sugar and high-temperature cooking.

Genotypes

• GG (Gly/Gly): typical AGE signalling

• GA (Gly/Ser): higher inflammatory response

• AA (Ser/Ser): highest AGE accumulation

What this means

If you carry the Ser allele, charred foods, fried foods and sugary products can have a bigger impact on inflammation, skin ageing and metabolic health. Antioxidant-rich foods (berries, herbs, turmeric) and gentle cooking methods are protective.

TCF7L2 (Transcription Factor 7-Like 2) — Insulin Release and Diabetes Risk

SNP: rs12255372

This gene affects how effectively your pancreas releases insulin.

Genotypes

• GG: normal insulin secretion

• GT: reduced β-cell performance

• TT: significantly reduced insulin output

What this means

If you have the T allele, your body may struggle with blood sugar spikes. Balanced meals (protein + fibre + healthy fats) and lower-GI carbohydrates help keep glucose stable.

KCNJ11 (Potassium Inwardly-Rectifying Channel Subfamily J Member 11) — First-Phase Insulin Release

SNP: rs5219 (E23K)

Controls the potassium channel that triggers early insulin release after meals.

Genotypes

• GG (E/E): strong early insulin response

• GA (E/K): reduced insulin release

• AA (K/K): weakest response

What this means

If your early insulin release is impaired, you may experience post-meal fatigue or cravings. Magnesium intake, balanced meals and regular movement can support glucose control.

GLUT2 (Glucose Transporter Type 2) — Sugar Transport and Sweet Preference

SNP: rs5400 (Thr110Ile)

Influences how efficiently you transport glucose/fructose and how sensitive you are to sweetness.

Genotypes

• CC: typical sugar sensitivity

• CT: increased sugar preference

• TT: strongest sweet cravings and altered glucose sensing

What this means

If you have the Ile allele, managing sugar cravings becomes essential. Natural sweeteners (allulose, erythritol), fruit-based snacks and removing sugary foods from the home environment can help.

FTO (Fat Mass and Obesity-Associated Gene) — Appetite, Satiety and Weight-Gain Risk

SNP: rs9939609

FTO does not change protein structure but shifts the way your brain regulates hunger.

Genotypes

• TT: typical appetite

• AT: increased appetite and snacking

• AA: highest hunger drive

What this means

The A allele is strongly linked with grazing, portion size and preference for calorie-dense foods. Protein-rich meals and planned eating strategies reduce its impact.

DRD2 / ANKK1 (Dopamine Receptor D2 / Ankyrin Repeat And Kinase Domain Containing 1) — Reward, Cravings and Emotional Eating

SNP: rs1800497 (Taq1A)

This variant reduces dopamine receptor density, changing how rewarding food feels.

Genotypes

• GG (A2/A2): normal reward processing

• GA (A1/A2): mild reward deficiency

• AA (A1/A1): strong reward deficiency → cravings and emotional eating

What this means

If you carry the A1 allele, your brain compensates by seeking more stimulation — often from high-calorie foods. Supporting dopamine through protein, exercise and non-food rewards is key.

Summary Table

Are Your Genes Contributing to Weight-Loss Resistance?

If you feel like you’re doing “everything right” but still struggle with appetite, cravings, carb intolerance or stubborn weight, your genetics may offer missing insights.

If you’d like support with testing or interpretation, you can book a consultation or contact me to order a test.

Reference list:

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Álvarez-Martín, C., Caballero, F.F., de la Iglesia, R. and Alonso-Aperte, E. (2025) ‘Association of MC4R rs17782313 genotype with energy intake and appetite: A systematic review and meta-analysis’, Nutrition Reviews, 83(3), pp. e931–e946. Available at: https://doi.org/10.1093/nutrit/nuae075

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