Blood sugar control: Dietitian names breakfast foods with a higher glycaemic index than orange juice

Solen Le Net

By Solen Le Net, 


Published: 09/04/2026

- 12:32

Updated: 09/04/2026

- 13:03

Popular morning staples such as cereals, toast and fruit smoothies can trigger sharp spikes in blood sugar

Most people can recite the rules of blood sugar control, yet millions unwittingly sabotage their mornings with risky breakfast choices, nutrition experts have warned.

Dietitian Dr Carrie Ruxton highlights that meals high in carbohydrates but low in protein are rapidly absorbed by the body, causing glucose to flood the bloodstream.



The issue is especially pronounced at breakfast, according to Ruxton, as many people fail to construct a balanced meal at breakfast, even though they do at lunch and dinner.

"One of the most common mistakes people make at breakfast is assuming that starchy carbohydrates have a lower impact on blood sugars," she told GB News.

YOGHURT AND GRANOLA

Granola frequently contains substantial added sugars and refined grains

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Both white and wholegrain varieties of bread rank high on the glycaemic index, meaning their carbohydrates are swiftly absorbed and cause rapid glucose elevation.

Surprisingly, pure orange juice actually has a lower GI than bread, despite its reputation as a sugary beverage.

Research published in the Food & Function journal found that pectin and polyphenols present in fruit help moderate the rate at which sugar enters the bloodstream.

Registered dietitian and VP of Behavioural Medicine at Numan, Zoe Griffiths, has identified what she terms "naked carbohydrates" as a key culprit.

This refers to consuming carbs in isolation, such as plain toast or fruit alone, without accompanying nutrients to moderate absorption.

The morning meal presents particular challenges because overnight fasting leaves the body primed to respond rapidly to incoming glucose.

"A common breakfast mistake is choosing carb-heavy, low-protein foods (like cereal, toast, or smoothies), which are quickly absorbed and can cause sharp blood sugar spikes," Griffiths noted.

But simple adjustments can significantly improve the morning glucose response, with Dr Ruxton recommending the addition of protein, healthy fats and fruit to breakfast helps moderate carbohydrate absorption.

Practical options include spreading avocado on toast, mixing nuts and seeds into cereal, or pairing a banana with a croissant.

BOWL OF CEREAL

Consuming carbohydrates in isolation can cause blood sugar levels to soar

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"Switching to sourdough bread lowers the GI, as does spreading nut butter instead of jam," she explained.

These modifications ensure that glucose enters the bloodstream more gradually, avoiding the sharp spikes and subsequent crashes that leave many feeling sluggish by mid-morning.

Griffiths also recommends consuming approximately 30 grams of protein per meal for optimal satiety.

She notes that while blood sugar fluctuations remain a normal part of digestion, flattening these peaks through dietary changes offers meaningful benefits.