A very quick blog as I know I haven't posted a whole lot recently. The title doesn't even do this justice… if you're reading this blog you're probably fairly happy with the fact that lowering your carbohydrates is a perfectly good way to lose weight. There is discussion, that is warranted, as to whether preferentially lowering carbohydrates actually has a significant advantage for fat loss but what is not worth discussing is whether eating more than the recommended 30-35% is bad for your health. This is a ridiculous concept that I touched on in my radio interview on Tuesday.
In the video below Gary Taubes, a journalist and science writer who is a strong proponent of low carb diets, discusses how dietary guidelines are based on bad science. He explains that weight loss is possible on low carbohydrate, high fat diets. Dr Dean Ornish (author of the Ornish Diet) who is a proponent of VERY low fat diets (low fat to the extent the government don't even recommend them) says that while high fat diets may cause weight loss they 'block arteries' and reduce blood flow to the heart. Just as an aside, if you don't have time to watch the whole video below but you are a fan of Taubes I would recommend skipping forward to 26:30 when he… well, I'll let you watch. Also, if you watch the whole video and are interested in Dr Barbara Howard's points about 'Ketosis' and how this is a bad thing, you can refer to this paper from Clinical Cardiology.
This brings me onto a study that has recently had a press release. You can read about it here: Losing Belly Fat, Whether from a Low-Carb or a Low-Fat Diet, Helps Improve Blood Vessel Function
I can't wait until this is published officially but I'm just going to pick out a few little bits from the lead author Professor Kerry J. Stewart, Ed.D. the director of clinical and research exercise physiology at the Johns Hopkins Heart and Vascular Institute. Just a heads up, the low fat diet in this case was not VERY low fat, it was simply less than 30% fat. The low carbohydrate diet was up to 30% of calories from carbohydrate. So, here are four quotes for you that I hope need huge explanation:
After six months, those who were on the low-carb diet lost an average of 28.9 pounds versus 18.7 pounds among those on the low-fat diet
These results showed no harmful effects from the low-carb diet
Stewart notes that participants on the low-carb diet lost more weight and at a faster pace, on average, which has also been seen in several other studies. He says eating higher amounts of carbohydrates can slow down the rate of body fat loss while on a weight reduction diet.
These longer-term results show that weight loss, along with exercise, is important for improving vascular health, and suggests following a low-carb diet rather than the conventionally recommended low-fat diet for weight loss is not a concern in terms of vascular health.
So what have we learnt? We have learnt that in this study a low carb diet was as good as, if not better, than a low fat diet for weight loss and that losing belly fat via either diet helps improve blood vessel function. So the question I ask is: "Why are so many people told to eat a high carbohydrate, low fat diet by doctors and dietitians if they need to lose weight?" Even the ridiculous dietitians at Diabetes UK, who recommend carbohydrate at every meal for diabetics, acknowledge low carb diets are effective for weight loss. (Read the Diabetes UK position statement on Low Carb Diets).
I've not read this yet but here is an article written by Volek et al "Low-Carbohydrate Diets Promote a More Favorable Body Composition Than Low-Fat Diets" I assume they will mention this study published last May by Kreider et al (2011) which concluded:
A carbohydrate-restricted diet promoted more favorable changes in weight loss, fat loss, and markers of health in obese women who initiated an exercise program compared with a diet higher in carbohydrate. (click to see abstract)
It might not mentioned the following study but you guys might be interested:
Severely obese subjects with a high prevalence of diabetes or the metabolic syndrome lost more weight during six months on a carbohydrate-restricted diet than on a calorie- and fat-restricted diet, with a relative improvement in insulin sensitivity and triglyceride levels, even after adjustment for the amount of weight lost.
This study used less than 30g of total carbohydrate per day! So we are probably looking at a ketogenic diet in this case. Anyway, I'll leave it there but I'm still dumbfounded by the dietary advice that is being given by 'qualified' individuals as well as what is being taught to medical students. My physio saw a very overweight woman in clinic who had just been for her session with the NHS dietitian. The extent of the advice given was that she needed to lose 10kg+ and that she should do so by lowering her fat intake and increasing her carbohydrate intake to 60% of her calories. Now, I'm told by my 'fans' who are dietitians that 'I don't know what it is like to only have 15 minutes per patient" and "I should try it sometime.." but in the case that I DID only have 15 minutes with this patient… guess what I wouldn't have told her?
Eat less fat and eat most of your calories from carbohydrates [/FAIL]
I'll leave it there, a slightly longer post than I wanted to write in the early hours of the morning but I will leave you with this gem of a study title:
DON'T FOR GET THOUGH A high saturated fat diet is more likely to make you obese than diets with lower saturated fat content. – IN RATS!!!!!!!!!!!!!! [/Head slap!]
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