Low Carb Diets - What Are They... And Do They Work?
>> Monday, June 19, 2017
One of the more currently in vogue weight management approaches is a low carbohydrate diet. I get asked about this a lot, so I figured it's time to put my thoughts in e-print! I'm going to take this in two parts. Today's blog will be about low carb diets in general, and the second will be about the low carb diet in people with diabetes.
So, what is a low carb diet exactly? Well, they have many names and forms: low carb, lower carb, very low carb, lower carb high/healthy fats (LCHF), ketogenic. Definitions of each of these vary, making comparisons and scientific study challenging. However, we can generally categorize these diets as follows:
Low Carb:
- providing less than 45% of the day's calories, OR
- less than 130g of carbs per day (= 520 calories)
Ketogenic or Very Low Carb:
- maximum carbs of 20-50g per day
LCHF : (low carb, high/healthy fat)
- the amount of carbohydrate recommended varies, but would fall in the low carb zone as defined above
- the restriction in carb calories is replaced with healthy fat choices
So, does a carbohydrate restricted diet result in more effective weight management? When compared to a low fat diet, the studies suggest that while there may be superior weight loss in the short term (eg 6 months), there is no difference after 1 year. The bottom line of the extensive studies on dietary composition shows that there is no particular macronutrient composition (carbs vs protein vs fat) that is superior to another when it comes to weight loss.
What is important is finding a permanent lifestyle change that works for each individual, and the composition of that diet is going to vary based on taste preferences, cultural differences and so forth.
I often hear of people feeling that they are being instructed to eat too many carbs, more than they actually want to eat. Their health care providers are probably following the teachings of Canada's Food Guide (CFG), which many obesity experts (including myself) would argue advises a carbohydrate intake that is too high for many people at up to 65% of total daily caloric intake. Remember that Canada's Food Guide (CFG) was designed for weight maintenance in adults, but that the majority of Canadian adults have overweight or obesity. Ergo, the CFG is only applicable to a minority of Canadian adults. Also, the average woman age 50+, and the average man age 70+, will gain weight following the CFG recommendations.
Most dietary guidelines recommend at least 45% carbohydrate, in order to limit excessive intake of saturated fat. It is important that the fats in our diet are the healthier unsaturated fats - in fact, the Mediterranean style of eating, which provides 35-47% of calories as fat, has been shown to reduce the risk of cardiovascular disease and breast cancer.
For some people, a restricted carbohydrate intake may work well - it eliminates the option of grabbing many high calorie food items on the run (eg bakery, vending machine, coffee shop products and so forth). There are also some people who may have an addiction-type response in their brain circuitry to high sugar foods, and avoiding these may help to break the cycle of overeating. But it's definitely not for everyone.
I often hear of people feeling that they are being instructed to eat too many carbs, more than they actually want to eat. Their health care providers are probably following the teachings of Canada's Food Guide (CFG), which many obesity experts (including myself) would argue advises a carbohydrate intake that is too high for many people at up to 65% of total daily caloric intake. Remember that Canada's Food Guide (CFG) was designed for weight maintenance in adults, but that the majority of Canadian adults have overweight or obesity. Ergo, the CFG is only applicable to a minority of Canadian adults. Also, the average woman age 50+, and the average man age 70+, will gain weight following the CFG recommendations.
Most dietary guidelines recommend at least 45% carbohydrate, in order to limit excessive intake of saturated fat. It is important that the fats in our diet are the healthier unsaturated fats - in fact, the Mediterranean style of eating, which provides 35-47% of calories as fat, has been shown to reduce the risk of cardiovascular disease and breast cancer.
For some people, a restricted carbohydrate intake may work well - it eliminates the option of grabbing many high calorie food items on the run (eg bakery, vending machine, coffee shop products and so forth). There are also some people who may have an addiction-type response in their brain circuitry to high sugar foods, and avoiding these may help to break the cycle of overeating. But it's definitely not for everyone.
In terms of weight maintenance and prevention of weight gain after weight loss, there is evidence to suggest that a higher protein, lower glycemic index diet may be better than a lower protein, higher glycemic index diet.
Stay tuned for part II: Can people with diabetes safely eat low carb?
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