b2d nugget: portion size is out; energy density is in for effective weight management

You'd think with bigger sizes, folks would feel more full after a feeding than with smaller sizes. Apparently not so.

In 2005, researchers were interested in whether the increase in portion size at restaurants and in snack foods was contributing to the obesity epidemic. Rightfully they acknowledge that while that would SEEM to make sense, it's tough to say so conclusively.

So what they did look at was - does eating more make one feel more full (and so maybe eat less at any point?). They also looked at "energy density" - how many calories are packed into a food item with the same weight (broccoli low ed; ice cream, high) - to see if that had an effect on fullness.

 british nutrition foundation "feed yourself fuller" chart

Here's the simple takeaway: big pig portions don't leave one more satisfied. But we all know small portions can leave one feeling well hungry. So, solution? Help folks start to mix in low energy dense foods, and that's way more successful than asking them to cut the fat. Guess what? weight loss ensues as their energy uptake (amount of calories a day) goes down.

Here's the abstract

The increase in the prevalence of obesity has coincided with an increase in portion sizes of foods both inside and outside the home, suggesting that larger portions may play a role in the obesity epidemic. Although it will be difficult to establish a causal relationship between increasing portion size and obesity, data indicate that portion size does influence energy intake. Several well-controlled, laboratory-based studies have shown that providing older children and adults with larger food portions can lead to significant increases in energy intake. This effect has been demonstrated for snacks and a variety of single meals and shown to persist over a 2-d period. Despite increases in intake, individuals presented with large portions generally do not report or respond to increased levels of fullness, suggesting that hunger and satiety signals are ignored or overridden. One strategy to address the effect of portion size is decreasing the energy density (kilojoules per gram; kilocalories per gram) of foods. Several studies have demonstrated that eating low-energy-dense foods (such as fruits, vegetables, and soups) maintains satiety while reducing energy intake. In a clinical trial, advising individuals to eat portions of low-energy-dense foods was a more successful weight loss strategy than fat reduction coupled with restriction of portion sizes. Eating satisfying portions of low-energy-dense foods can help to enhance satiety and control hunger while restricting energy intake for weight management.

That last line says "eating satisfying portions" - which means that portions can still be pretty unfettered IF you're eating low energy density food. I wrote awhile ago how making mounds of greens super edible just by adding some really good balsamic vinegar. The beauty is, low energy density foods are also often HIGH in nutrient density. So, for instance, leafy greens are rich in macro and micronutrients while being low in kcals.

There's another related study in 2007 that shows however IF you can encourage folks to cut the fat a bit, after awhile, we don't miss it. So again another strategy towards saving kcals and weight management. Here's the abstract about how this finding was constucted:

This study establishes the reliability and validity of the Fat Preference Questionnaire^©, a self-administered instrument to assess preference for dietary fat. Respondents select the food which tastes better and is eaten more frequently from 19 sets of food. Each set is comprised of related foods differing in fat content. The questionnaire was administered to women in laboratory-based (n=63), cross-sectional (n=150), and weight-loss (n=71) studies. The percentage of food sets in which high-fat foods were reported to “taste better” (TASTE score) and to be “eaten more often” (FREQ score) was determined. A measure of dietary fat restriction (DIFF) was created by subtracting TASTE from FREQ. Food intake was assessed by direct measure, 24-h recall, or food diary. Additionally, participants completed a standard survey assessing dietary restraint. Test–retest correlations were high (r=0.75–0.94). TASTE and FREQ scores were positively correlated with total fat intake (r=0.22–0.63). DIFF scores positively correlated with dietary restraint (r=0.39–0.52). Participants in the weight-loss trial experienced declines in fat consumption, TASTE and FREQ scores, and BMI values, and an increase in DIFF scores. Weight loss correlated with declines in FREQ (r=0.36) scores and increases in DIFF scores (r=−0.35). These data suggest that preference for dietary fat declines when following a reduced-fat diet and an increase in restraint for intake of dietary fat is important for weight loss. The Fat Preference Questionnaire^© is a stable, easily-administered instrument that can be used in research and clinical settings.

That's cool. We happily adapt. SO of course someone had to look at the combination of some reduced fat and some engery density lowering foods together. Backlash? not at all. Good results:

BACKGROUND: Consuming foods low in energy density (kcal/g) decreases energy intake over several days, but the effectiveness of this strategy for weight loss has not been tested. OBJECTIVE: The effects on weight loss of 2 strategies for reducing the energy density of the diet were compared over 1 y. DESIGN: Obese women (n = 97) were randomly assigned to groups counseled either to reduce their fat intake (RF group) or to reduce their fat intake and increase their intake of water-rich foods, particularly fruit and vegetables (RF+FV group). No goals for energy or fat intake were assigned; the subjects were instructed to eat ad libitum amounts of food while following the principles of their diet. RESULTS: After 1 y, study completers (n = 71) in both groups had significant decreases in body weight (P < 0.0001). Subjects in the RF+FV group, however, had a significantly different pattern of weight loss (P = 0.002) than did subjects in the RF group. After 1 y, the RF+FV group lost 7.9 +/- 0.9 kg and the RF group lost 6.4 +/- 0.9 kg. Analysis of all randomly assigned subjects also showed a different pattern of weight loss between groups (P = 0.021). Diet records indicated that both groups had similar reductions in fat intake. The RF+FV group, however, had a lower dietary energy density than did the RF group (P = 0.019) as the result of consuming a greater weight of food (P = 0.025), especially fruit and vegetables (P = 0.037). The RF+FV group also reported less hunger (P = 0.003). CONCLUSION: Reducing dietary energy density, particularly by combining increased fruit and vegetable intakes with decreased fat intake, is an effective strategy for managing body weight while controlling hunger.

 The main thing in this last finding it seems is that again, we don't have to fiddle portion size on the plate particularly - which folks have a difficult time with as we looked at back when considering stupid set point theory  -  BUT get the mix of lowering fat and upping VOLUME of low energy dense food - which means good colours on the plate too, that we get to reduced caloric intake without feeling like we're starving.

Related resources:

• b2d nutrition index
• respect the fat
• what's a "whole protein" - esp. going veggie
• set point theory is crap
• why is fish oil anti-inflamatory?

Citations

Ello-Martin JA, Ledikwe JH, & Rolls BJ (2005). The influence of food portion size and energy density on energy intake: implications for weight management. The American journal of clinical nutrition, 82 (1 Suppl) PMID: 16002828

LEDIKWE, J., ELLOMARTIN, J., PELKMAN, C., BIRCH, L., MANNINO, M., & ROLLS, B. (2007). A reliable, valid questionnaire indicates that preference for dietary fat declines when following a reduced-fat diet Appetite, 49 (1), 74-83 DOI: 10.1016/j.appet.2006.12.001

Ello-Martin JA, Roe LS, Ledikwe JH, Beach AM, & Rolls BJ (2007). Dietary energy density in the treatment of obesity: a year-long trial comparing 2 weight-loss diets. The American journal of clinical nutrition, 85 (6), 1465-77 PMID: 17556681