Compared to the reduced carbohydrate diet, the reduced fat diet led to a roughly 67% greater body fat loss<\/em>.\u201d Wow \u2013 67% – how impressive is that? Completely unimpressive as it turns out…<\/p>\nThe calorie requirement established during the first five days of 50% carbohydrate, 35% fat, 15% protein was considered to be 2,720 \u00b1 50 calories. This would be my first challenge. My weight is stable and yet my calorie intake is different every day to the next. I don\u2019t see how a fixed calorie intake number can be established at all, let alone in five days.<\/p>\n
Notwithstanding this, the study reduced calorie intake by 30% for the subjects for the next 6 days \u2013 the reduction to either come entirely from fat intake or entirely from carbohydrate intake.<\/p>\n
If someone is having 2,720 \u00b1 50 calories in the percentages 50% carbohydrate, 35% fat, 15% protein, they are having 1,360 carb calories, 952 fat calories and 408 protein calories. The study reported removing 790 \u00b1 20 calories from both diets \u2013 all of these to come from carbohydrate intake for the LC group and all 790 \u00b1 20 calories to come from fat in the LF group. This resulted in the following balance of macro nutrients:<\/p>\n
The LC group ended up with a diet comprising 30% carbohydrate, 49% fat, and 21% protein.<\/p>\n
The LF group ended up with a diet comprising 72% carbohydrate, 7% fat, and 21% protein.<\/p>\n
The problems<\/strong><\/p>\nYou can immediately see one of the problems. This should have been called RC and LF \u2013 Reduced Carb and Low Fat. The fat intake at 7% is absurdly and unnaturally low; the carb intake at 30% is way higher than any genuine low carb diet. Hence this was not comparing a low carb with a low fat diet. It was comparing a reduced carb diet with an unnatural fat intake.<\/p>\n
The body fat loss for the 6-day intervention was calculated as 394 grams<\/em> for the low-fat group and 236 grams for the reduced-carb group. The difference is 158 grams \u2013 about the weight of an apple. However, 158 grams divided by the smaller of the 2 numbers (236) = 67% and that\u2019s where the 67% comes from.<\/p>\nEven more disingenuous is the method of calculation. I wondered how body fat lost could possibly even be calculated to that degree of accuracy (because it can\u2019t). The briefing paper shared the methodology: \u201cThe researchers measured the amount of fat eaten and the amount of fat burned, and the difference between them determined how much fat was lost from the body during each diet<\/em>.\u201d<\/p>\nWhat?! The researchers have assumed that dietary fat has no other use within the body \u2013 any eaten needs to be burned and that\u2019s all that can happen. That is a completely invalid assumption. Fat is the most versatile macro nutrient to the body. It can be used for energy and it can (and is) used for the maintenance and growth of every cell in the body.<\/p>\n
The low fat group consumed hardly any fat during their intervention \u2013 135 calories of fat daily, which is about 15 grams. The reduced carb group maintained the same fat intake as in the weight maintenance phase \u2013 952 calories = 106 grams. There was a 91 gram difference in daily fat intake. If we average the grams of fat claimed to have been lost over the 6 days, the LF group allegedly lost 66 grams a day and the RC group allegedly lost 39 grams a day. But the difference is more than three times accounted for by intake.<\/p>\n
The low fat group consumed barely any dietary fat to be used for cell maintenance and repair. The entire fat intake of the restricted carb group could have been used up in body maintenance and growth.<\/p>\n
Even if the calculation is as simple as grams of fat eaten \u2013 grams of fat burned = grams of fat lost, and it isn\u2019t, we can reverse engineer the numbers to show that the reduced carb group were burning 145 grams of fat a day vs. 81 grams of fat a day being burned by the low fat group. So the headline could have been \u201creduced carb diet burns almost twice as much fat as low fat diet.\u201d<\/p>\n
Weight loss vs. fat loss<\/strong><\/p>\nThe headline could also have been \u201creduced carb dieters lost 46% more weight than low fat dieters\u201d. This was a finding of the study \u2013 the average weight loss with the reduced carb diet was 1.9kg in 6 days; the average weight loss with the low fat diet was 1.3kg in 6 days \u2013 that\u2019s a difference of 46% if you want to play the misleading relative numbers again. A genuinely low carb diet (under 10% carb intake) could have achieved a 2-3kg loss in 24 hours, as approximately 500g of glycogen would have been depleted and approximately 2kg of water along with it.<\/p>\n
Where does this leave us?<\/strong><\/p>\nThe briefing paper did at least acknowledge: \u201cLong-term extrapolation of our results is fraught with difficulties<\/em>.\u201d However, this didn\u2019t hold the researchers back from the conclusion: \u201cWhile fat oxidation during prolonged LF and LC diets would be expected to slowly wane over time, our data suggest that the greater fat imbalance is likely to persist with the LF diet leading to more long-term body fat loss than with the LC diet<\/em>.\u201d<\/p>\nHall also shared with James Gallagher the challenges of the diet \u2013 even in just six days: “It’s not easy, these folks had to eat the same meals every day. This was very strictly controlled and they had to eat the food provided and nothing else, the diets got pretty boring pretty quickly<\/em>.”<\/p>\nCould a 7% fat diet be done \u2018free-range\u2019? Highly unlikely. Should<\/em> it be done \u2018free-range\u2019? Absolutely not. The reality is that a diet with 72% carbohydrate intake and 7% fat intake is unhealthy in the medium, let alone long, term. It would not deliver the essential fatty acids and fat soluble vitamins, A, D, E and K, so vital for human health and survival, let alone the macro nutrient requirements for body maintenance and repair.<\/p>\nWhile this was a well designed and controlled study, therefore, it is difficult to see how this leaves us with anything useful to take away. Surely the time would have been better spent studying a diet that could actually be recommended and sustained, if shown to be of any benefit, and to report results more scientifically than a headline-grabbing relative risk based on an invalid assumption that comes down to the weight of an apple.<\/p>\n","protected":false},"excerpt":{"rendered":"
A story emerged on March 5th 2015 from the annual meeting of the Endocrine Society in San Diego. It was<\/p>\n","protected":false},"author":2,"featured_media":4887,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1057,1079,1102,4,1090],"tags":[966,521,317,964,253,432,963,283,1002,965,165,33],"_links":{"self":[{"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/posts\/3538"}],"collection":[{"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/comments?post=3538"}],"version-history":[{"count":2,"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/posts\/3538\/revisions"}],"predecessor-version":[{"id":3540,"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/posts\/3538\/revisions\/3540"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/media\/4887"}],"wp:attachment":[{"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/media?parent=3538"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/categories?post=3538"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zoeharcombe.com\/wp-json\/wp\/v2\/tags?post=3538"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}