Banish The ‘Broscience’ Pt 2 : Protein Shakes & Blood Sugar

‘Bro you gotta be careful taking protein shakes if you’ve got Diabetes cos it causes high blood sugar levels!’

A little note to our Diabetic customers and cliental…Protein shakes and amino acid supplements DO cause an initial rise in blood sugar levels if they contain some carbohydrate (and most do), and the amount of carbs can be anything from 0.5g to 35g+ per serving. However, it is not this potential initial rise in blood sugar levels that Diabetics need to consider, rather it’s the rise in INSULIN. Insulin is the hormone released by the pancreas which serves to unlock the muscle and bodily tissue ready for carbs, amino acids and fat to enter, however in Diabetics insulin either isn’t produced or released from the pancreas (Type 1 or advanced Type 2 Diabetes), or it loses some or all of its effect (Type 2 Diabetes)…basically the ‘key’ (insulin) is no longer being manufactured, or the ‘key’ no longer fits the ‘lock’ (insulin receptors on the muscle and tissue).

In the context of this article I will refer mainly to Type 2 Diabetes. So when insulin receptivity and effectiveness is hindered, the blood sugar levels can become a concern…but not necessarily in the way your ‘Bro’ may have you believe! You see it’s not so much the risk of high blood sugar levels that’s the concern in Type 2 Diabetes, but rather the risk of compensatory lows such as when insulin levels rise after the consumption of a protein shake. In response to a protein or amino acid shake your body’s blood sugar levels increase slightly, but it is the drop in blood sugar that follows maybe 15-20mins after the insulin release that needs to be factored by your average ‘Bro’. According to Salehi, Gunnerud, Muhammed, et al. (2012), amino acids (protein) cause a greater insulin release than pure glucose (see Figure 1 below), so interestingly this causes most of the sugar/glucose and amino acids in the blood to enter the muscle and bodily tissue. Consequently the level of sugar in the blood drops meaning hypoglycaemia (low blood sugar) is a real risk (Mayo Clinic, 2012).

Figure 1 : Insulin response after consuming a protein or amino acid shake


(Salehi, Gunnerud, Muhammed, et al. 2012)

The Cocktail + GIP bar is basically the insulin response to the combined ingestion of amino acids and glucose and demonstrates the importance of Diabetics consuming regular starchy carbs over the course of the day in order to deliver a ‘drip feed’ of sugar to compliment the rise in insulin after a protein or amino acid shake. This reinforces the Diabetes UK recommendation of not going more than 2-3 hours without a source of food, ideally comprising a starchy carb e.g. oatmeal, sweet potato, wholegrain pasta or rice (Diabetes UK, 2013).

In order to keep blood sugar levels relatively constant, minimising those undesirable peaks and troughs (ups and downs) associated with Diabetes, three regular meals should be consumed every day including breakfast, lunch and an evening meal, as well as a starchy carb snack in between meals (mid-morning, mid-afternoon and mid-evening).

So what you actually get when you consume a protein or amino acid shake is a momentary rise in blood sugar, followed by a compensatory drop in blood sugar because insulin has done its job, enabling protein and glucose to enter the cell for growth and energy!


Mayo clinic, (2012). Whey Protein. Retrieved 7th Feb, 2013, from

Salehi, A., Gunnerud, U., Muhammed, S, J., Ostman, E., Holst, J, J., Bjorck, I, & Rorsman, P. (2012). The insulinogenic effect of whey protein is partially mediated by a direct effect of amino acids and GIP on β-cells. Nutrition & Metabolism9:48

About the Author

Job Role Qualified Dietitian and Sports Nutritionist Qualifications BSc (Hons) Sports Science | BSc (Hons) Dietetics Tom has always participated in sport both recreationally and competitively which led to an unquenchable thirst for information on anything health, nutrition and fitness. After leaving school Tom went on to play for a football academy during which time he studied Sport and Exercise Science. From here he went on to study a BSc (Hons) Sport Science at UEA followed by his second BSc (Hons) degree, this time at the University of Hertfordshire studying Dietetics. Tom has worked in the fitness, educational and clinical nutrition industry starting out at David Lloyd Health and Leisure Clubs. He then went on to work as a Dietitian (RD) in the NHS, during which time he conducted clinics for healthy eating, weight loss and weight gain, as well as specialised consultations on Diabetes, IBS and Coeliac disease to name a few. He has vast amounts of experience at devising diet plans and supplement regimens, as well as working in the community with schools and competitive athletes. As Head Nutritionist and Supplement expert at Discount Supplements Tom is here to provide current and evidence based health and nutrition information to help you reach your health and fitness goals!
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