The next time you tuck into a protein rich dinner, it may be a good idea to hold off on the sugary drinks. A new study published in BMC Nutrition found that a combination of sugar sweetened drinks and a protein rich meal decreases metabolic efficiency, which can lead to more fat being stored. Here to tell us more is lead author of the study Dr. Shanon Casperson.
Let’s face it, sugar tastes good. Added sugars account for approximately 16% of total energy intake. That’s around 6 tablespoons (91 grams) of added sugar every day. The largest source of added sugars in our diet is from sugar-sweetened drinks. This is why a large amount of research is focused on the health effects of these types of drinks.
The beneficial effects of protein-rich diets are well documented. Increasing protein intake increases satiety, increases metabolism and decreases energy intake. But what happens when we drink a sugar-sweetened beverage with our steak dinner? How does this change how our body processes and uses the nutrients from the meal?
To answer these questions, we asked volunteers to spend 24 hours in a metabolic chamber on two separate occasions. The metabolic chamber is a 12-by-10-foot hermetically controlled room. This allows us to measure exactly how the body is using the nutrients from the foods. By having someone stay in a metabolic chamber, we can determine how many grams of carbohydrate, protein and fat the volunteer is using and how many calories they’re burning every minute.
To fully understand how the volunteer used the nutrients from the meals, we measured oxygen consumption, carbon dioxide production and urinary nitrogen excretion. Nitrogen is a key component of protein and the amount excreted in urine provides an estimate of protein breakdown. Once protein utilization is known, the amount of carbohydrate and fat utilization can be correctly calculated from respiration.
For all testing procedures, the volunteers ate the exact same foods throughout the day. During one of the visits, they ate a diet consisting of 15% protein and for the other visit they ate a diet consisting of 30% protein. At each meal, they had either a sugar-sweetened drink or an artificially sweetened drink. After each meal, we asked the participant about their hunger and desire to eat certain types of foods.
The body only expended 80 of the 120 kcals that was provided by the sugar-sweetened drink
We found that drinking a sugar-sweetened drink with a meal significantly decreases fat use and diet-induced thermogenesis (heat production). And when we paired the sugar-sweetened drink with a protein-rich meal, the combination further decreased fat use and diet-induced thermogenesis by more than 40%. Additionally, we found that, over the course of a day, the body only expended 80 of the 120 kcals that was provided by the sugar-sweetened drink, thus creating a 40-kcal surplus independent of how much protein was in the meal.
These results highlight the impact that consuming a sugar-sweetened drink can have on energy balance and fat use. One implication of the results is that the body’s reduced metabolic efficiency after drinking a sugar-sweetened beverage can lead to a greater tendency to make and store fat. Our findings provide further insight into the potential role of sugar-sweetened drinks in the etiology of obesity.
MurphysLab on July 22nd, 2017 at 14:17 UTC »
This is good and very valid science, with a conclusion that is very likely to be correct, contrary to what the current top comment reads:
So to analyze why this is good science and likely valid, let us examine the study and its design:
The study was pre-registered (At ClinicalTrials.gov: NCT02211599), with a clear outline of the scope and methods (protocols) to be used. This avoids bias where only hypothesis-affirming data are reported and hypothesis-contradicting data are hidden or discarded. This has been a major problem for pharmaceutical research as well as other types in the past. Additionally, this avoids p-value hacking (FiveThurtyEight has a great interactive tool for playing with data to see how your choices affect the p-value) and spurrious relationships (which are often found in nutritional studies), where sub-group analyses (obligatory xkcd) are performed to find "significant" relationships. Upon inspection, it appears that the study followed the design posted. The study was peer-reviewed. In fact, this manuscript was examined using an "open peer review" process, in which alongside the study, the reviewers' original comments are posted and names given, here. With the reviewers and editors names and comments all being open, as is the case at this journal, BMC Nutrition: "The peer reviewers and editors are fully accountable for the decisions made, bias is reduced as reviewer reports are named, published reports can serve an educational purpose in helping facilitate training and research into peer review, and reviewers can get credit for their work." The reviewers affirmed the following: "the methods appropriate and well described" "the work include[s] the necessary controls" "the conclusions drawn [are] adequately supported by the data shown" Whether they are "able to assess any statistics in the manuscript" The reviewers also declare whether they have any "competing interests" The paper is published in (what most scientists would consider to be) a reputable journal that is operated by a major publisher, BioMed Central, which is owned by the publishing giant, Springer Nature. Other good publishing indicators are that the journal is sponsored by a major scientific society and that esteemed scientists regularly publish in it.The experiments are rigorous and relevant: First, this is attested to by the reviewers who are more qualified in the field than I am (they're both professors in human nutrition; I'm a chemist / (nano)materials scientist). But as an outsider to the field, here are my observations:
The study controls for external variables (age, sex, lean body mass, diet for 3 days prior) It excluded those with characteristics which would complicate or invalidate the analysis (e.g. lactating / breastfeeding mothers have an energy output that would not be measured by the study's methods). Summaries of the 29 subjects' characteristics and habitual dietary intake are provided They monitor outputs relevant to the metabolic processes in humans: O2 consumption; CO2 emission, thermal energy, air pressure, and nitrogen in urine. > Volunteers spent "24 hours in a metabolic chamber on two separate occasions. The metabolic chamber is a 12-by-10-foot hermetically controlled room. This allows us to measure exactly how the body is using the nutrients from the foods. By having someone stay in a metabolic chamber, we can determine how many grams of carbohydrate, protein and fat the volunteer is using and how many calories they’re burning every minute." There's a baseline for control: > During one of the visits, they ate a diet consisting of 15% protein and for the other visit they ate a diet consisting of 30% protein. The statistical methods and equations are supplied TIL Doppler radar can be used to for activity level monitoring indoors (e.g. a thesis on the topic). Neat!The primary results are clear and present statistical significance:
A p-value of less than 0.05 is considered significant. The effect of beverage type has a p-value of 0.0356. Second obligatory xkcd. I've summarized the corresponding data below, although using different units: Fat Oxidation (grams of fat / kg of lean body mass / day) MALES 30% Energy from Protein 15% Energy from Protein Sugary Drink (SSB) 2.26 ± 0.59 g/kg(LBM)/day 2.45 ± 0.69 Artificially Sweetened Drink (NNSB) 2.52 ± 0.62 2.53 ± 0.73 FEMALES 30% Energy from Protein 15% Energy from Protein Sugary Drink (SSB) 2.40 ± 0.84 g/kg(LBM)/day 2.50 ± 0.8 Artificially Sweetened Drink (NNSB) 2.58 ± 0.89 2.72 ± 0.72From the publication:
Note: the inference used here is that if you are not oxidizing the fat that you eat (a.k.a. "burning fat"), then you are storing the fat that you eat. Hence the data show that the sugar-sweetened beverage results in reduced fat burning, and the effect is bigger when more of the diet's energy comes from protein.
From the linked summary:
The ancillary results show no unexpected or confounding surprises. This would not necessarily invalidate a paper, however it is a factor which increases the reader's assurance that nothing weird is going on.
e.g. 24h Energy Expenditure is very strongly correlated with lean body mass... as you would expect.The publication is open access: This is how science should ideally be done. It doesn't hurt to give a quick read to what is published before jumping all over the conclusions, as some are in the habit of doing. Even if it is not open-access, articles often are published to pre-print servers (e.g. Arxiv.org for physics) or to the researchers' own online spaces.
No conflict of interest arising from the authors' personal interests or those of the funding agency or sponsors.
The research was conducted as part of an academic research program at the University of North Dakota. "The work is funded by the United States Department of Agriculture (USDA): This work was supported by the Agricultural Research Services of the United States Department of Agriculture #5450–51,530-051-00D. The role of the finding sponsor was to approve the study and the submission of this manuscript for publication." "The authors declare that they have no competing interest."One additional thing worth taking note: Many may not have realized, but the linked article is written by the first (and corresponding) author of the article which it summarizes. Hence the scientist here is likely not over-stating the results, as often happens with science journalism.
Edit 1: I hit submit too quickly, so if you're reading and see this comment, I'm still writing.
Edit 2: Done.
Edit 3: Added point #8, that there is no conflict of interest.
DiskoBonez on July 22nd, 2017 at 13:26 UTC »
To put it more positively, the best way to store fat is to combine sugary drinks with a protein rich dinner.
aigroti on July 22nd, 2017 at 12:48 UTC »
So are sugary protein shakes pretty bad then?