Glycemic Index

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The foods we eat affect our blood sugar in different ways. Some cause a quick spike in energy followed by a crash, while others release energy more slowly and steadily. The Glycemic Index (GI) is a simple tool to measure this effect.

What does GI mean?

  • GI = Glycaemic Index.
  • It’s a number from 0 to 100 showing how quickly a carbohydrate-containing food raises blood sugar, compared with pure glucose (set at 100).¹
  • Foods are grouped into:
    • Low GI (≤55): Slow, steady release of sugar — keeps you fuller for longer.
    • Medium GI (56–69): Moderate effect.
    • High GI (≥70): Fast release of sugar, quick spike then a drop.²
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Why does it matter?

  • Energy balance: Low GI foods provide longer-lasting energy and help avoid mid-afternoon “slumps.”³
  • Weight & appetite: Because they release energy slowly, low GI foods help control hunger and prevent overeating.⁴
  • Diabetes management: A low GI diet helps stabilise blood sugar levels, reducing spikes and dips.³
  • Heart health: Long-term, a low GI pattern is linked to healthier cholesterol levels and lower risk of type 2 diabetes.⁴
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Tips for everyday eating

  • Mix & match: Combine high GI with low GI foods (e.g. white rice + lentils) to lower the overall effect.
  • Choose whole: Whole grains, beans, and legumes usually have a lower GI than refined carbs.⁴
  • Add fibre & protein: Vegetables, beans, chicken, eggs, and fish slow digestion and reduce blood sugar spikes.
  • Snack smart: Replace sugary drinks, biscuits, or crisps with fruit, yoghurt, or nuts.

The Glycemic Index is not about avoiding all high GI foods — it’s about balance. Aim to include more low- and medium-GI foods in your daily meals, especially if you are managing diabetes, weight, or heart health.

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Low GI (55 and below – best for steady energy)

  • Beans (sugar beans, kidney beans, black beans) – 27–35
  • Lentils – 32
  • Chickpeas – 33
  • Apples – 36
  • Oranges – 40
  • Pears – 38
  • Sweet potato (boiled) – 44
  • Brown rice – 50
  • Wholewheat bread (dense/seeded) – ~50
  • Maize meal (stiff pap) – ~50
  • Plain yoghurt (unsweetened) – 35
  • Peanuts – 14
  • Proteins (no GI impact but important to include): Chicken, fish, beef, eggs, cheese – GI ≈ 0
  • Milk (full cream / low fat, unsweetened) – GI 30–35
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Medium GI (56–69 – use in moderation)

  • Basmati rice – 58
  • Oats (rolled) – 58
  • Banana (ripe) – 62
  • Pineapple – 59
  • Maize meal (soft porridge) – 65
  • Brown bread (lighter commercial loaves) – 60–65
  • Sweetcorn – 60
  • Instant noodles (plain) – 63–65
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High GI (70 and above – limit these)

  • White bread – 75
  • Cornflakes – 81
  • Rice Krispies – 82
  • White rice – 73
  • Pumpkin – 75
  • Watermelon – 72
  • French fries (chips) – 75
  • Doughnuts – 76
  • Biscuits (Marie / tea biscuits) – 70–75
  • Chocolate bar (milk chocolate) – 70+
  • Packet of crisps (potato chips) – ~75
  • Cup of tea with 2 sugars – ~70
  • Can of Coke – 77
  • Can of Red Bull – 75–77
  • Can of beer (lager) – ~66–70 (varies, but spikes blood sugar quickly)
  • Jelly sweets / candies – 80+

 

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  1. Diabetes South Africa. Glycaemic Index. diabetessa.org.za
  2. Atkinson FS, et al. International Tables of Glycemic Index. Am J Clin Nutr. 2008.
  3. Sweet Life Diabetes Community. Fast Facts: All about Low GI. sweetlife.org.za
  4. FoodFacts South Africa. Glycaemic Index Database. foodfacts.org.za

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