Low carb, high protein and high fat diet - Prof Tim Noakes
Like most dietitians when I heard of Prof Noakes' latest opinion
on nutrition I was horrified and initially thought he had lost the
plot! But after further consideration, I rationalised with myself
that he is a very educated and well-read person and he would not
make such a statement without sufficient reason. And so began my
quest to gain insight and understanding of what has lead him to
this radical approach. The low carb was one thing, but the comment
that saturated fat is not the culprit for heart disease was
something I just could not get my head around!
Firstly, the important point to stress is that this way of eating is specifically applicable to those people who are "carb-resistant", or at risk of developing diabetes, and not specifically for athletes. Typically, if you are one of these candidates then you will have a strong family history of type 2 diabetes (non-insulin dependent), you may very well have a high BMI (i.e. well above the healthy limit of 25), and you may have been told that you are insulin resistant, or pre-diabetic. Everyone else, should continue with what we dietitians recommend and that is a balanced high carb (low GI, of course), moderate protein and moderate fat diet.
1. Reduce your carb intakeIn the quest to limit fat (because it is calorie dense and therefore made sense to restrict in order to manage weight), sugar has crept into people's diets to a point of excess and large amounts of (particularly) refined carbs can cause detrimental changes in our blood lipids, i.e. raised triglycerides and raised levels of smaller dense LDL particles (which are strongly associated with atherosclerotic coronary heart disease) and lowered HDL (the good cholesterol). We (dietitians) know however, that moderate amounts of fats are in fact really important to promote healthy functioning of cells and to promote satiety and thus control portions at meal times (hence controlling weight), and we would generally encourage largely low GI carbs throughout the day to promote good energy levels, support blood glucose levels and maintain good weight management. And for most people that I see in my practice this works like a charm! But for those who are carb-resistant, it seems that a restricted carb intake may produce greater weight loss, and this in turn produces favourable changes in blood lipids and therefore reduces their risk of heart disease and diabetes, and those who exercise are able to perform better at a lower weight.
To lower your carb intake:
• Limit added sugar to no more than 3-6 tsp per day, and try to cut it out completely!
• All high sugar foods and drinks need to go too! For example, ice cream, desserts, chocolates, sweets, many fat-free products are higher in sugar (so read the labels) and especially all sugary drinks
• The amount of carbs each person ideally needs will vary and therefore each person (ideally with the help of a dietitian) should slowly reduce portions of carbs throughout the day until you establish the minimum that you are able to still function optimally on. Carbs remember will include all starchy foods (bread, rice, pasta, potato, corn, peas, crackers) and fruit. During this process also identify all refined carbs and replace them with low GI, unrefined alternatives. For example, get rid of white bread, and choose heavy seeded low GI bread rather, choose whole wheat pasta rather than white pasta, have sweet potato rather than normal baked or mashed potato, make cooked oats (made with milk to lower the GI) rather than processed cereals, choose beans and legumes to bulk out meals thus keeping the overall GI low.
• Aim to have a small amount of low GI carbs at every meal and snack to spread your carbs evenly as you taper your intake down. These carbs may be present in typical starchy foods (as mentioned above), or fruit or dairy.
The fat issue:
• Prof Noakes is quite right (obviously!), it seems that under certain circumstances saturated fat does not impact on blood lipids in the way we would expect. In fact, provided that sufficient amounts of polyunsaturated (PUFA) (i.e. omega 3) and monounsaturated (MUFA) fats are consumed, SFA does not seem to increase heart risk, through altered blood lipids. But my question which still needs answering is how much SFA can be present to still maintain the benefits of sufficient amounts of PUFA and MUFA? It is too early to say at this point, and therefore, in my opinion, those people with significant heart risk in their family history should be wary of adopting this approach until such time as things are clearer.
• Finally, then, if carbs are reduced higher protein is needed to provide that sense of satiety after a meal. And remember that if sufficient healthy fats are consumed the theory is that the SFA in these foods should not affect heart risk. However, until more quantitative information is available, I would still recommend low fat and lean options, because the focus is on getting enough healthy fats - so rather make greater allowance for these fats to be added than having high fat protein foods.
Whether endurance athletes following this low carb approach can sustain their activity over 90 minutes, when we would normally encourage carbo-loading and certainly carb fuelling during these long events, remains to be seen. Perhaps they would need to revert to a lower level of carb fuelling during these events, with or without carbo-loading, particularly if they exercise at higher intensities, versus those who exercise at relatively low intensities. Clearly this is going to be a very interesting area of research. For now these athletes will have to establish their own solutions, but I would recommend seeking the assistance of a sports dietitian, and keeping a close eye on all health parameters, including keeping a food and training diary to record the process.
Compiled by: Keri Strachan - Registered Dietitian
Prime Human Performance Institute
Shop 2 & 3 Moses Mabhida Stadium
Tel: 082 448 6696