How to Manage Blood Sugar for Health & Body Composition

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Written by Astrid Naranjo (Clean Health Accredited Clinical Dietitian)

Blood sugar management is important for health and body composition, more in the long term that it is short term or acutely, however, some clients may be more susceptible than others to perceive and be affected by acute blood sugar fluctuations (mood, energy, cognitive function, etc). Long term nutritional management of blood glucose dysregulation seems to be strategically correlated to the prevention of chronic diseases associated to insulin resistance and diabetes type 2 (1).

There is mechanistic evidence to suggest that elevated blood glucose levels contribute toward development of type 2 diabetes mellitus (T2DM) (2). Moreover, high blood glucose levels, including values that are below the cut-off for the diagnosis of diabetes, have been shown to be associated with an increased risk of cardiovascular events (1).

These days everyone has become so heavily focused on energy balance that many fitness professionals are just sending their clients to My Fitness Pal allowing them to eat whenever and whatever they like as long as it fits within their daily macros target.

This is a cop out by the trainer for two reasons. Firstly, it can cause decision fatigue, which can lead clients to making poor food choices and being less adherent to their diet. Secondly, it can cause blood sugar highs and lows which can create a host of problems in the body.

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Long periods without eating or overconsuming high glycaemic foods can cause blood sugar levels to drop rapidly and trigger a stress response by the body, which may cause norepinephrine and epinephrine to flood our bloodstream. While these stress chemicals are required to mobilize energy and fuel, they are a double-edged sword, and chronically elevated levels can be problematic (1-3).

Chronic stress and unable to manage this on a daily basis can also impact blood sugar levels not just daily, but also overtime. It is well known that acute stress elevates catecholamines that may cause additional effects such as sweating, rapid heartbeat, increased body temperature, anxiety, tremors, nausea, heart palpitations, and hunger, which are all symptoms commonly associated with hypoglycaemia (3,4).

In addition, poor glycaemic control, including both high and low blood glucose, has been associated with negative mood states such as anger, anxiety, and depression, and impaired cognitive performance (4-6). That would make it much more difficult for someone that’s not managing their blood sugar levels properly to adhere to their diet plan.

In fact, studies have shown those with insulin resistance are 50-80% more likely to overeat following a moderate or high glycaemic meal compared with a low glycaemic meal and have better adherence to a low carbohydrate diet (7,8). That could also be related to insulin resistance of the brain, which can blunt the satiety signal from insulin (8,9).

That is why it is important to have an understanding and appreciation of why managing blood sugar is so crucial, especially in those with insulin resistance, which makes up a significant portion of the population. A study from 2012 reported about 50% of all US adults have problems with blood sugar management (pre-diabetics and diabetics) (9,10). The prevalence of diabetes across other nations around the globe is equal to or even greater than in the United States, especially in the Western Pacific, Middle East, and North Africa (10,11).

This is why it’s not enough to just give your clients a daily macro goal and send them off to My Fitness Pal and hope that they will hit their daily targets. For the majority of your clients you will need to either teach them or give them an agreed/discussed nutrition plan with suggestions of what foods, how much and how often to eat while staying within their calorie and macro targets. This will help with adherence to their meal plan and promote better blood sugar management (especially if they are beginners or they truly struggle with an initial set up of their choices on their own).

Here are 5 basic recommendations for helping manage blood sugar levels:

1. Exercise Regularly and resistance train
Exercise has a significant impact on blood glucose management. That’s because exercise increases both insulin-independent and insulin dependent muscle glucose uptake (12). A combination of aerobic and resistance training may be more effective for blood glucose management than either type of exercise alone (12).

There is evidence to suggest that resistance training produced a more significant reduction in HbA1c level as compared to cardiovascular exercise. Hence, an optimal exercise program for individuals (especially those with insulin resistance/diabetes) should include a resistance training component to be effective in improving the overall metabolic profile, and thus reduce the risk for long term diabetic complications in type 2 diabetes (29).

Those with insulin resistance or metabolic syndrome should perform at least 150 minutes of moderate to vigorous aerobic exercise spread over a minimum of 3 days per week, with no more than 2 consecutive days in between bouts. Additionally, they should also perform resistance training at least 2-3 days per week (12).

2. Control Carbohydrate Intake
Several recent systematic reviews and meta-analysis have showed that controlling carbohydrate intake is effective for improving glycaemic control (13-15).

Controlling carbohydrates doesn’t mean eliminating carbohydrates altogether or following a very low carbohydrate diet. At this point there is not enough evidence to conclude which type of diet is optimal for glycaemic control, and it may vary from person to person. Studies have shown that low carbohydrate diets, low GI diets, the Mediterranean diet, and high-protein diets, are all effective for improving glycaemic control (15).

That’s because when we add protein, fat, or fibre to a meal, it slows down the rate of entry of glucose into the bloodstream which helps maintain more stable blood sugar levels. What we want to avoid is overconsuming too many high glycaemic, low fibre carbohydrates in one sitting, to prevent the blood sugar highs and lows.

A recent meta-analysis showed that habitual consumption of sugar sweetened beverages was associated with a greater incidence of type 2 diabetes, even when adjusted for adiposity (16). Assuming there was causality, consuming sugar sweetened beverages over many years may be related to a substantial increase in the onset of diabetes.

3. Increase Fiber Intake
As mentioned previously, fibre slows the digestion of carbohydrates and the rate of entry of glucose into the bloodstream. Several recent meta-analysis and systematic reviews have shown that increasing fibre intake improves glycaemic control (17,18). The recommended daily fibre intake of is about 14 grams for every 1,000 calories consumed (18).

4. Eat at Regular Times
At this point the optimal meal frequency for improving glycaemic control has not been well established or agreed upon. Most intervention studies have found conflicting results defining whether more meals are better (19,20).

When it comes to health and blood sugar management, several studies have shown that eating smaller more frequent meals could be associated with improved glycaemic control, lower hunger and greater satiety (21-22).But at the end of the day this is very individual. Some benefit and find better response from a more frequent meal pattern, others don’t.

As a dietitian, and from experience with many patients and clients, maintaining a regular eating schedule (regardless of the frequency) by avoiding snacking and skipping meals, may be more important than the meal frequency for keeping stable ghrelin and insulin levels throughout the day.

Ideally breakfast should be consumed within two hours of waking up, lunch should be consumed before 1pm, and dinner should be consumed no later than 2hrs before bedtime. Some people may do better having their breakfast and dinner a bit later. However, I still recommend having breakfast within 2hrs of waking up, lunch before 3pm, and dinner no later than 2hrs before bedtime (23). One study showed that ideally up to 50% of the total daily calories should be consumed at least 8hrs before the onset of melatonin, to optimize the circadian timing of food intake (24).

Lastly, several studies have shown that consuming a low carbohydrate or low GI breakfast can improve glucose tolerance at subsequent meals (25-27).

5. Ensure Adequate Micronutrient Intake
Several micronutrient deficiencies have been linked to hyperglycaemia and carbohydrate intolerance. Most notably that includes potassium, magnesium, chromium, calcium, vitamin C, vitamin D, and zinc (28).

Outside of taking a multivitamin supplement and consuming a balanced diet including a minimum of 5 servings of fruits and vegetable a day, I do not recommend taking therapeutic doses of any micronutrient unless you have specifically identified though blood work that your client has a deficiency, or that they are not getting an adequate amount from their diet.

In summary, blood sugar management is important for health and body composition, more in the long term that it is short term or acutely, however , some may be more susceptible than others to perceive and be affected by acute blood sugar fluctuations (mood, energy, cognitive function, etc). Long term nutritional management of blood glucose dysregulation seems to be strategically correlated to the prevention of chronic diseases associated to insulin resistance and diabetes type 2.


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  17. McRae MP. Dietary Fiber Intake and Type 2 Diabetes Mellitus: An Umbrella Review of Meta-analyses. J Chiropr Med. 2018;17(1):44–53. doi:10.1016/j.jcm.2017.11.002
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  28. Chehade J, Sheikh-Ali M, Mooradian A. The Role of Micronutrients in Managing Diabetes. Diabetes Spectrum. 2009;22. 214-218. 10.2337/diaspect.22.4.214.
  29. Bweir, S., Al-Jarrah, M., Almalty, AM. et al. Resistance exercise training lowers HbA1c more than aerobic training in adults with type 2 diabetes. Diabetol Metab Syndr 1, 27 (2009).

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