HOT off the Press!
A very important, and intriguing study ( needs to be replicated), that offers new insights into how the body adapts and reacts to different carbohydrate and fat percentages in the diet!
Its design was very elegant with immediate real time weight measurements via WiFi connected scales, daily weighing that prompted immediate calorie adjustments! The food was provided and was free, and participants also received monetary compensation.
This was a transparent government initiative study; no conflicts of interest were reported.
What was already known on this topic was that: Energy expenditure (how your body burns calories) declines with weight loss, predisposing to weight regain. Little is, however, known about how dietary composition (carbohydrates, protein and fat contents) influences this adaptive metabolic response (burn rate response) over the long term.
164 overweight men and women of many ethnicities had to lose 12% of their body weight on a genetic diet with lower calorie content in order to enter the study, that means that those were highly motivated people that wanted to succeed! When they reached this 12% weight loss, they were then randomized to 3 diet groups that would run for 20 weeks. In all groups, the calorie target was 2001 kcal diets but with different CARBOHYDRATE (CHO) contents; the LOW CHO at 20% and thus HIGH FAT at 60%, the MEDIUM CHO at 40% with MEDIUM FAT at 40%, and finally the HIGH CHO at 60% with LOW FAT at 20%. PROTEIN (PRO) content was kept steady at 20%! The reason to keep protein steady is that protein metabolism (burning) in the body has a so called “thermic” effect, it means that burning protein costs more for the body than burning other stuff. So, doing this meant that any differences found would be accounted for by the CHO and the FAT only.
The researchers measured TOTAL ENERGY EXPENDITURE per day using DOUBLY LABELED WATER METHOD (https://en.wikipedia.org/wiki/Doubly_labeled_water ) which is an excellent estimate of how many calories our bodies burn! Then they also measured some hormones like INSULIN (hormone from pancreas that lowers sugar), GHRELIN and LEPTIN secretion.
They found that our bodies burned 52 calories more per 10% decrease in CHO contents of our diet! That meant that people in the LOW CHO group burned between 210 and 280 with a mean of 250 calories (when fully adjusted for all confounding factors) MORE than the HIGH CHO group.
More importantly, these numbers were even higher in the people with HIGH INSULIN SECRETION before weight loss, that means the people that probably were INSULIN RESISTANT (also looked at in the study with significant results) and at risk to develop diabetes! In the highest third of insulin secretion that difference was almost 500 calories per day that is double the calories compared to the normal insulin production group! This highlights a subgroup (probably pro-diabetic!) who could do particularly well with restriction of total or high glycemic load carbohydrates.
Triglycerides were LOWEST and HDL (good cholesterol) was HIGHEST in the LOW CHO group as well compared to the other 2 groups! Compliance to the study was measured by spot checks on weight and the use of WiFi connected scales and with a blood test that can detect ingestion of carbohydrates on top of what was prescribed, and was found to be around 98%!
The authors say that: “If this effect (the observed difference in calories between the LOW and HIGH CHO groups of 250 calories per day) persisted—and we observed no attenuation from 10 to 20 weeks—it would translate into an estimated 10 kg weight loss after three years for a typical 30 year old man of height 178 cm, baseline weight 100 kg, and average activity level, assuming no change in energy intake. If reduction of glycemic load (LOW CHO HIGH FAT group) also decreased hunger and food intake, the long-term benefits could be even greater.”
Another interesting finding was that GHRELIN, produced primarily in the stomach, was significantly LOWER in participants assigned to the LOW CHO carbohydrate diet, a novel finding. Beyond effects on hunger, ghrelin has been reported to lower energy expenditure (make our body burn less calories) and promote fat deposition (increase fat under the skin and in the abdomen)!
LEPTIN (a hormone from fat cells that signals body energy stores) was also LOWER in participants assigned to the LOW CHO carbohydrate diet, suggesting improvement in leptin sensitivity. Prospective studies have observed that people with the greatest declines in leptin levels after weight loss have the lowest risk for weight regain (the lower our leptin, the better the chance not to regain weight).
There are strengths and limitation in the study and instead of going through all, we should wait and see whether future studies can reproduce these results.
In conclusion, the COMPOSITION of our DIET seems to have an impact on how our bodies BURN those CALORIES.
How will you know how much of your diet comes from carbohydrates, fat or protein?
There are many websites that provide those services for free BUT you will NEED TO WEIGH what you EAT and register it in these websites that will then give you an estimate of total calories and a percentage of carbohydrate, fat and protein content of your diet. Avoiding foods with added sugar, flour, rice, noodles and other refined carbohydrates could help when you start and is a must to achieve carbohydrate contents of 20 to 40%. These foods seem to undermine your metabolism anyway. Sugar-laden drinks, alcohol drinks are also to be avoided.
If you need more information please refer to articles in our website (https://www.olympicambrosia.com/) or other notes here in our FB account.