January 2017 Question 2
2. The 88 participants
in this studies sample were randomized into one of two types of
energy-restricted diets. The study describes the diets as the following.
Both diets were energy-restricted (1,200 kcal/day for women and 1,500
kcal/day for men), with 20% energy deriving from fats (<10% from saturated
fats), and accompanied by daily multivitamin supplements. However, the HPD
derived 3 4% of energy from proteins and 46% from carbohydrates, whereas the
HCD featured 17% energy from proteins and 63% from carbohydrates.
(Calugi, Marchesini, Ghoch, Gavasso, and Grave, 2017).
(Calugi, Marchesini, Ghoch, Gavasso, and Grave, 2017).
The researchers of this
study concluded the type of energy-restricted diet was not a significant
influence on participant weight loss per weight loss goal or weight maintenance
per weight satisfaction.
Why did the researchers
come to this conclusion? Do you agree with the study’s conclusion that the
placement in either described diet would not affect weight loss or weight
maintenance? Does your experience with metabolism support or question the
study’s conclusion?
posted by Unknown @ 7:47 PM
13 comments
13 Comments:
2. I believe the researchers came to the conclusion that type of energy-restricted diet was not significant because participants on both diets showed comparable weight loss. The calorie content of both diets was equivalent, with differing macronutrient distributions. In terms of the most basic weight loss principle of “calories in--calories out” or “a calorie is a calorie,” this conclusion makes sense. With equal energy intakes in both diets, it is expected that weight loss amount would not differ. I am curious as to how other health factors were affected by the type of diet used, such as blood sugar control. I do not expect that weight loss amount or maintenance would vary by diet type. My knowledge of metabolism, particularly from FCS 420 Advanced Metabolism, suggest that calories all calories are not created equally. In terms of CHO, foods with more fiber per calorie will have less of an effect on blood sugar and insulin levels than a food of equal calories with less fiber. The nutritional quality of the calories consumed is important for overall health, but I am unsure how this would affect strictly weight loss. The quality of the foods that make up the total calorie count is perhaps more important than total calorie intake in terms of overall health, and possibly weight loss.
Before reading the results, I assumed that weight loss would not have differed, if just basing results off of diet. The amount of calories consumed was the same in both categories, and if they expended roughly the same amount of calories among both groups, the results make sense. While the study does suggest that there is no significant correlation between macronutrient breakdown and weight loss/maintenance, I do see benefits in the ratio with more protein (34% protein, 46% carbohydrates) for long term weight maintenance. Protein increases satiety and preserves muscle mass. Including a fair amount of lean protein into ones diet will help with satiety and may aid in consuming fewer calories. But with that said, I still agree with the study that a specific diet ratio does not affect weight loss/maintenance.
Kirsten, I like what you pointed out about the importance of the quality of the foods that make up the total calorie count rather than just the total calorie intake. With weight loss being the focus, it is important to be choosing the high fiber foods for satiation (prevent overeating), lean protein for maintaining muscle mass, etc. for overall health and possible weight loss.
I also agree with the author's conclusion that type of diet does not influence total weight loss. As stated by Nikki and Kirsten, both diets contained similar caloric energy and therefore both groups reacted similar to the hypocaloric restrictions. As Kirsten stated, diet quality transcends total caloric intake, so it is important to consider what items were included on the participants food diary. As with most diets, recommendations are often not one size fits all, so I would imagine that some might benefit more from one diet category than the other. Based on the study design and data, there is no way to recollect whether any participants experienced better metabolic consequences than others. We do know that both diets recommended a balance of carbs, fats, and proteins which when accompanied by proper vitamins, minerals, and water, is a safe approach to weight loss.
Both diets restricted calories and research shows that calorie restriction (especially when combined with increasing physical activity) results in weight loss. Therefore, the findings of this study indicate that the way calories are restricted (reducing CHO or Protein) is not as important as the overall reduction in calories consumed. So, when working with a client you can tailor your diet recommendations to meet each person’s needs/preferences. However, I would be cautious about recommending such a low-protein diet such as the HCD used in the study with weight loss clients because weight loss often results in muscle loss as well as fat loss. Therefore, I would recommend physical activity and a diet with 20 to 35 percent protein to limit muscle loss.
All four contributors determined the researchers conclusions were correct, that type of diet did not significantly contribute to weight loss or maintenance.
Multiple points were raised as to the preference of either presented diet.
- Additional metabolic markers may indicate improved healthfulness, such as blood sugar level, for a particular diet not reflected in the measure of weight loss.
-Inclusion of sufficient protein may improve adherence to diet through enhanced satiation despite kcal restriction.
- Restriction of kcal for weight loss from protein sources may contribute weight loss resulting of loss of lean body mass.
Both diets were considered to hold the same potential for weight loss despite macro-nutrient ratios in relation to equal restriction of kcal.
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Kirsten and Justine established insufficient data was presented to comparatively analyze the benefits or flaws of the two diets. What additional measures would you be interested in seeing in judging these calorie restricted diets?
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Similarly to others, despite the differing macronutrient distribution of the two groups, both research groups intervention were similar with calorie-restrictive diets of 1,200 kcals and 1,500 kcals for women and men respectively. Because the nature of both diets was the same, I do not see why there would be significant differences in weight lost or management. If the two diet groups had different approaches to weight loss, for example: calorie-restrictive and the Mediterranean diet, the study may have seen some larger differences between groups.
I have not seen many "low protein, high CHO" calorie-restricted diets and with my nutritional knowledge, I was a bit apprehensive about this distribution of macronutrients. With weight loss, I would not recommend limiting protein because I would want my clients to preserve their lean body mass. However, both groups mainly focused on reducing calories to result in weight loss; thus, I am not surprised both groups saw similar weight loss.
In response to Rachel's follow-up post, I think measuring %fat and %lean body mass would help shed light on which of the featured diets provided more benefits. As Noel and Kandice mentioned, it is important those seeking weight loss preserve their lean body mass, so keeping track of what type of weight is lost would be important.
Contrary to a few of my classmates, I assumed that the two types of energy-restricted diets would have an influence on participant weight loss per weight loss goal based on my knowledge of Metabolism. Calories in must be lower that calories out is an oversimplified weight loss theory. Then again, as mentioned, nutrition quality plays a role in weight loss along with other factors. Based on the study’s results, I believe that it is fair to assume that the placement in either prescribed diet did not affect weight loss or weight maintenance. However, I would not have suggested that the HCD go any lower with energy from protein due to an increased risk for loss of lean body mass rather than body fat. More tests would need to be done to see if there were any other effects that the diet differences had on both groups.
I feel that an energy-restricted diet would have the same outcome of weight loss, which is what the researchers concluded. By putting the body in an energy-deficit, coupled with low-intensity exercise (walking), this results in the same weight loss since the target calorie ranges for women and men were the same--just different macronutrient distributions. While these diets may be comparable in outcome, I feel that neither of them are realistic in a long-term setting. I feel that many of these participants may end up regaining the weight, as this weight loss program was not specifically focused on changing behavior. There was a component of nutrition education, but this didn't seem correlated with the particular variables analyzed.
I agree with Noel and Krista- I would be very apprehensive to advise a client to follow a high carbohydrate-low protein diet. As these ladies have already mentioned, I do not want my clients to loose muscle mass, especially as regular physical activity would be part of the weight loss regimen recommended. From a metabolic perspective, this type of diet would deplete the labile amino acid pool and may limit certain substrate usage as well as lead to the possibility of micronutrient deficiencies (long-term). On a larger scale, clients following a high CHO/low protein diet would have less satiety than clients that would follow a high protein/low CHO diet. This correlates with Nikki's insight on increased adherence to the prescribed diet with high levels of satiety.
I am not very surprised that the results of this study concluded both energy restricted diets resulted in the same weight-loss outcome. In this study, diet was recorded by the patient daily in a food log, and then reviewed by the RD in each session. Having completing my community rotation at SPEC, I often observed the RDs having to discuss with patients about being honest when recording their diet in their food diaries. It is very easy for individuals to leave items out in their food diary that may create confound results, thus resulting in similar results for both restricted diets. There could be other reasons as well, but this is a common limitation observed when using self-reported food logs. The best way to complete this study would be providing controlled diets to the participants, which is often not feasible.
Noel, I like how you pointed out there were no major differences between the diets selected. Your suggestion of comparing calorie restrictive to the Mediterranean may produced more interesting results. Many of you also commented on "calories in versus calories out". Although some research may suggest calorie reduction may not be as successful as we once thought, there is still a great amount of literature that supports this - and may be the main explanation for the results of this study.
I am not surprised the researchers came to this conclusion considering both of the groups had high calorie restrictions. Interning at DMH these past few weeks has enhanced my learning on losing weight and the metabolic process. Without knowing the quality of the type of food the participants are eating and focusing just on calories-in-calories-out I would be concerned about the participants depleting their muscle stores.
Kandice, as you mentioned and as I mentioned in the last post it is important to individualize all plans to each client/pt. I also agree with what you that reducing protein in a diet. Protein increases satiety and can help prevent someone from experiencing muscle loss. It is always important to lose weight in a healthy way and I feel that restricting protein wouldn't be the best way.
Kirsten, I think you brought up a good point about the quality of the calories consumed for overall health. This point also makes me wonder about the long-term feasibility of the diet. I feel that by providing education about the quality of calories and not just the quantity, the client would be better prepared to reach their long-term weight loss goals and improve their overall health.
Kirsten, I like the point you make stating that you are curious about what other health factors came into play between the two diets. I would be curious to compare the participants lab values from each of the two groups to see what other factors came into play, such as HDL, LDL, and TAGS. You are right, not all calories are created equal and though both groups showed similarities in pounds lost, I wonder if either of the diets altered their metabolic panel.
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