The Truth about Blood Sugar
Besides diabetic patients who don’t have enough insulin to control their blood sugar levels and bodybuilders who wish to spike their insulin levels for anabolic gain, you don’t tend to hear much discussion about blood sugar management in sport. It is in fact the FIRST thing that you should be getting right in your dietary program.
Whether you are an athlete or simply a couch surfer, many of you are victim to the sugar rollercoaster on a daily basis. Think back to the last time you consumed a Danish pastry or sweetened cup of coffee– the likelihood was that you felt good and energetic for a while, but this gradually gave way to feelings of fatigue, poor concentration, sleepiness and hunger. And so then you downed another sugary coffee!
Many problems with our health can stem from poor management of blood sugar levels. Energy is most undoubtedly affected by the sugar highs and lows, but have you also noticed that your mood goes along for the ride – excitable and focused progressing towards irritable and anxious. These are just the things that you notice – behind the scenes. You may be experiencing a slow build up of fat reserves in anticipation of the fast that never comes; your body can become inflammatory, which doesn’t help recovery from hard training sessions and believe it or not, it can raise susceptibility to overtraining or even adrenal burn-out.
So why should we be faced with all of these health irregularities due to simply liking a sugary start to the morning? Firstly, we need to look at our friend insulin – which if managed correctly, can offer a ton of benefits. Insulin signals the body to store nutrients which are absorbed from our diet, so if it’s some sugars and good quality proteins and/or amino acids straight after a workout, you will be kicked into an anabolic state, resulting in better recovery prospects and the ability to grow new muscle tissue. Just a side comment here – whether you are a body builder or strength athlete who actively wants to put on mass or an endurance athlete who doesn’t, you should actively seek an anabolic environment to ‘remodel’ your muscles and other connective tissues after training. However, what happens when you abuse your insulin?
The Blood Sugar Curve
Take a look at the blood sugar curves in Figure 1. If you follow the red curve for now, with that pastry coffee breakfast I mentioned earlier or even cornflakes with skimmed milk, for that matter, it will give you a nice sugary start to the day. Did you know that cornflakes have a higher GI than table sugar (1)?! Brekkie will probably give you a lift for an hour or two, but insulin is very effective at its job and by the time it’s kicked in, your blood sugar levels can drop quickly, meaning; low energy, poor concentration, sleepiness and hunger for more sweet food – just like a smaller scale hypoglycaemia.
So perhaps you take a coffee and a couple of biscuits to get yourself out of the blood sugar trough! Lunch is also a bit on-the-go and you grab a sandwich and low-fat/high-sugar fruit yoghurt whilst you sit at the computer (with your stress hormones still raised). Stress hormones themselves will actually raise blood sugar levels which is why many people are able to literally go through the day without eating. They also down-regulate your digestive function, so even if you do eat, the food won’t be absorbed so well. The afternoon follows a similar picture to the morning but more often with a more pronounced dip in energy and by the time you arrive home for dinner (especially after a gym workout where you only drink water, cause you’re trying to be ‘good’), you’re ready to eat a horse! When you do in fact eat the proverbial horse, the blood sugars drive so high and long that they set you into Sumo fat storage mode and sometimes you don’t sleep so well, thereby missing out on a nice anabolic growth hormone spike. Does this sound familiar? We’ll now examine what harm this approach can have on your body, despite readying you for a bout in the Japanese fighting ring.
This may be a term that you have heard of, as it is medically recognised as the precursor phase to diabetes (2). In actual fact, Insulin Resistance is very much a scale of many shades of grey, where black is full-blown diabetes, but we are all somewhere on the spectrum. It is a crucial survival mechanism whereby we are able to store fuel during periods of feast and therefore survive periods of famine. The few nomadic tribes still left in this world are testament to this theory – Aborigines in Australia and Pima Indians in America when left to their natural lifestyle of feeding off the land, will be healthy, strong and lean people. However, when adopting a Western refined diet and sedentary lifestyle, obesity, diabetes and heart disease tend to follow (2). This is the most extreme example of insulin resistance and it has been linked to the so-called ‘thrifty gene’ which some of us Westerners will have.
So yes, genetically you are prone to putting on weight, but this is all completely controllable through lifestyle and eating patterns. Neither of these tribes have in their diet, for example, sweetened breakfast cereals, bread, rice, pasta, sweets, pastries, cakes, crisps, low-fat cereal bars, low-fat fruit yoghurts, refined/processed foods, coffee and alcohol. Yet, that is what we load ourselves up with in the vague notion that low-fat diets will help us to lose weight.
After that side-line, I still haven’t explained what Insulin Resistance is: when blood sugar peaks (as shown in the red curve) insulin is responsible for pulling it out of the blood stream (where it is toxic in high quantities) and putting it into muscle and liver cells for energy. However, repeated abuse of this system (like multiple ‘hits’ per day) can eventually down-regulate the sensitivity of insulin receptors to this sugar. Instead of being used for energy, the sugar becomes converted into blood fats (3) or stored as fat in any of the body’s tissues, the biggest site being our Adipose Tissue, or fat that sits under your skin. The result is sluggishness in energy and generally an accompanying gain in body fat. What happens over time, is that more and more insulin will be released from your pancreas in order to remove the sugar from circulation – this means that the pancreas is working overtime and as with everyone who may work too much without the occasional holiday, it can burn out, resulting in diabetes (Type II), which is characterised by insufficient insulin to deal with the blood sugar spikes. Longer term problems of insulin resistance development include cardiovascular disease and possibly even Alzheimer’s Disease (4).
In a blood test, elevated blood sugars can be an indicator of diabetes and further tests are required. However, in the case of insulin resistance, blood sugar levels can appear quite normal, whereas insulin (which is generally not tested for) is likely to be raised. The same may apply to your cholesterol and triglyceride levels (3), which are generally tested for. Before I discuss insulin-management techniques, I want to share with you another couple of connections that insulin has in the body; adrenal stress and inflammation.
If you notice in the red blood sugar curve, cortisol is labelled next to the trough in blood sugar. Cortisol is your ‘slow-release’ stress hormone, whereas adrenaline is your fast release one. Cortisol is needed to wake us up in the morning, get us to work and keep us going through the day. It helps us to break down stored carbohydrate, fat and protein (muscle) in order to produce energy. By being activated, it increases sugar levels in the blood stream and is hence used when we need energy. If you are unable to balance your blood sugar levels through diet, as you can see in the red blood sugar curve, cortisol will repeatedly be called into action. Cortisol will also be called into action by all kinds of stresses: you can divide these into the 3 P’s of stress as defined by Medical Immunologist Dr. Alex Concorde (5). The first ‘P’ is for Psychology, or emotional and mental stresses; the second ‘P’ is Physical which is where your training comes into play plus demands of any physical job; the third ‘P’ is Physiological which means any imbalance in your body – examples could be your immune system reacting during the hayfever season or to a seasonal cold, any musculoskeletal damage such as training demands or injuries or a bit of IBS (irritable bowel syndrome).
Part of the physiological stress is a hormonal one – if your blood sugar is constantly bouncing up and down, in order to avoid hypoglycaemia, cortisol and some other hormones must be released every time you drop into a low. Just like the pancreas example, the adrenal glands can eventually burnout if they have enough additive stress to deal with over time. In athletes, another phrase for adrenal burnout is ‘overtraining’ (6) So, can you see the connection now between blood sugar regulation and overtraining? With a tight control of the sugars, you should be able to milk a bit more energy out of your body for training fuel and also experience more rapid training recoveries.
Without going into the detailed biochemistry of inflammation, I just want to look at the part it plays on blood sugar control. The omega 3 and 6 fatty acid pathways are an integral part of inflammation – you want enough of it to deal with new training stresses or injuries but not so much that it slows your recoveries and affects your overall health, which can happen in many overtraining cases. It has been shown that insulin aggressively stimulates a molecule that promotes the pro-inflammatory side of this pathway (7). So in addition to taking your fish, nuts, seeds and their oils (such as Super Omega 3 and Flax Seed Powder) in adequate amounts, it’s vital to keep the blood sugars balanced to control inflammation.
What we may be inclined to do when injured, is to feel sorry for ourselves and over-indulge in comfort foods and drinks. Now unless you find comfort in grilled salmon and steamed broccoli, typical comfort foods are the ones most likely to swing the blood sugars and imbalance the omega 3 and 6 inflammatory control. It essential you switch your mind onto active recovery by following the guidelines below.
Practical Guidelines for Managing Blood Sugar Levels
In essence it’s pretty easy to manage blood sugar levels and achieve the ‘green’ curve in the diagram above if you’re prepared to pay a bit of attention to your diet and spend some time off the stress treadmill. Let’s start with some foods or substances that you should be avoiding as much as you can and we’ll go onto discuss the best dietary and lifestyle approaches.
- Factors that can imbalance blood sugar levels:
- Sugar, refined foods and high GI foods (see Table 1)
- Foods that your body is allergic or sensitive to
- Nutritional deficiencies (such as vitamins, minerals, essential fats)
- Hormonal Imbalances (especially sex hormones)
- STRESS (the 3 P’s)
How to Balance Blood Sugars
The BOTTOM LINE with managing your blood sugar level, is to balance your carbohydrates, protein and fat intake at each meal. Protein and fat have very little effect on insulin and when digested along-side carbohydrates, will substantially slow the appearance of sugar in the blood and the related insulin response. The average person should be consuming roughly similar amounts of protein and carbohydrate-rich food in each meal or snack. The healthiest representation of this would be a small plate, one third filled with fish and two-thirds filled with vegetables. The fish provides protein plus ‘good’ fats. Vegetables mostly consist of water and fibre, so they are required in higher quantities than energy dense foods such as meat or grains. They are the best source of slow energy-releasing carbohydrates.
• Protein: Good sources are fish, poultry, red meat, eggs and soya (best from fermented sources such as tofu and miso). You can also get a complete protein source by combining beans or nuts with wholegrains (eg. lentils and brown rice). You can supplement your diet with protein powders such as Impact Whey Protein, Soy Protein or Egg White Protein. Whey is highly bioavailable and quick to absorb (perfect for post-exercise), while the others are slower (perfect for a snack or pre-bed).
• Carbohydrates: Focus on low GI carbohydrates such as vegetables, fruit and wholegrains (eg. brown rice, wheat, oats, millet, quinoa). Since we aim to have high intakes of vegetables in our diet, the average person who is not heavily active does not require many grains. In general, I like to increase grains in a person’s diet based on the amount of exercise that he or she is doing. In addition, minimise refined grains such as bread, pasta, white rice and pastries. Instant Oats are a great source of low GI carbohydrates and make a great addition to any smoothie.
• Essential Fats: Oily fish, nuts and seeds are perfect examples of EFA’s or ‘good’ fats. In addition, some saturated fat from good quality animal sources such as eggs and meat or vegetarian sources such as avocado and coconut is vital for giving stability to cell membranes and for making hormones, especially the sex and stress ones. Try using Coconpure instead of olive oil in your cooking for an easy and delicious way to incorporate essential fats into your daily meal plan.
In addition to Carb/Protein/Fat Balance in each meal and snack, these guidelines are useful:
- Eat a meal within one hour of waking
- Eat five times per day: 3 meals plus 2 snacks (plus an extra post-exercise one when working out)
- Distribute the quantity of food evenly throughout the day – breakfast, lunch and dinner should ideally be similar sizes.
- Do not go for more than 5 hours without eating
- Finish your final meal of the day at least 2-3 hours before bed time
- Vegetable consumption – aim for 5+ portions per day (1 portion = size of an apple)
- Fruit intake – aim for 2-3 portions per day, but no more than 4 because they are sugary (1 portion = size of an apple)
- Whole grains – reduce intake to a maximum of 2 portions per day (1 portion = 2 thin slices bread, 50g dry weight rice, pasta, oats). All grains (carbohydrates) should ideally be unrefined such as brown rice, bulgar wheat or quinoa. The more exercise you’re doing the more you can build your amounts.
- Protein – ensure some form of protein is taken at every meal
- Water – aim for 1-2 litres per day depending on needs
Table 1 – Glycaemic Index (1)
Exercise requires a special mention because the dynamics of insulin change a bit. During exercise, the muscles and other metabolic tissues are drawing sugar out of the blood stream and using up stored glycogen at a much faster rate than normal. It has been convincingly shown that if you take a sports drink during exercise, it will prolong your time to exhaustion (8). Whether you are interested in performance or not, if you take some sugars on-board during exercise in the form of ONE Isotonic, it should reduce the reliance on stress hormones (as shown in Figure 1), which is a good thing for long-term training. I also like to take a simple sugar like Maltodextrin or Waxy Maize Starch and mix in about 30g per ½ litre water. Fruit juice (½ and ½ with water) can be added for flavour and extra nutrients. A bit of L-Glutamine or Impact Whey Protein can also be added to support anabolic activity.
Post-exercise, it’s very important to get your timing of nutrients right. Figure 2 is a diagram from Ivy and Portman’s excellent book ‘Nutrient Timing’ (9). Exercise actually increases insulin sensitivity (10) and hence gives us a greater opportunity to restock some carbs and support muscle remodelling (otherwise known as anabolic activity). You can see that the first 45mins after exercise is the peak period to get your nutrients on-board. Compared to during exercise, this should favour more protein, with a good 20-40g scoop of your chosen protein powder (Impact Whey Isolate will be the fastest to absorb) plus 20-60g of carbs, depending on the duration and intensity of workout. My favourite is to make a smoothie out of True Whey, some carbs, 1-2 pieces fruit and natural yoghurt. If you prefer, or are simply rushed for time, Recovery XS combines the essential ingredients to help promote faster recovery.[CENTER]Figure 2 – Post-exercise Window of Opportunity (9)
So we have reviewed the importance of blood sugar regulation for health – in particular your energy, mood and waistline. Also of importance was the influence it has on adrenal health and whole-body inflammation, which are physiological functions that need to be balanced if you’re going to hit your physical peaks in sport and fitness. These concepts should have left you with a healthy respect for the hormone insulin, which given the stress and poor dietary patterns that we tend to throw at it, does a remarkable job – this system, like any other however, is breakable. Lastly, we looked at insulin’s role in sport, especially post-workout (the one time in the day that you should look to consume high GI sugars) and in effect, have your cake and eat it too!
Ian Craig MSc is an exercise physiologist, nutritional therapist, NLP practitioner and a coach. From a background in competitive middle-distance running, he specialises clinically in sports nutrition from an integrative health perspective. Ian is the Editor of the Functional Sports Nutrition magazine and he writes and presents internationally on this new concept.
1) Michel Montignac (1996). Dine Out and Lose Weight. 2nd Ed. Montignac Publishing (UK).
2) Lillioja S, Mott D et al. (1993). Insulin resistance as precursor of non-insulin dependent diabetes mellitus. Prospective studies of Pima Indians. NEJM. 29:1988-1992.
3) Bland (2007). Beyond Metabolic Syndrome: From Controversy to Improved Clinical Outcomes – Clarifying the Confusion Surrounding Popular Diets such as the Atkins, Zone, and Palaeolithic Diets. Metagenics Educational Programs. London, UK.
4) Steen E et al. (2005). Impaired insulin and insulin-like growth factor expression and signaling mechanisms in Alzheimer’s disease-is this type 3 diabetes? J Alzheimers Dis. 7(1):63-80.
5) Concorde (2005). The Basics and Beyond of PNI. The Concorde Initiative Course Notes. Royal Society of Medicine Sept 2005.
6) Craig I (2007). Overtraining as a model of overtraining. Nutrition Practitioner. 8(2): Autumn, 1-10.
7) Ash M and Kane P (2005). Fatty Acids 2005 Update. Nutri Link Ltd.
8) Coyle et al. (1986). Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. J Appl Physiol. 61:165-172
9) Ivy & Portman (2004). Nutrient Timing. Basic Health Publications Inc.
10) Heath G et al. (1983). Effects of exercise and lack of exercise on glucose tolerance and insulin sensitivity. J Appl Physiol. 55(2):512-517.
Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.