Weight Management & Satiety

Obesity is a multi-factorial and complex health issue. Current guidance for weight management encourages physical activity along with consuming an overall healthy eating pattern which includes whole grains, fruits, vegetables, lean proteins, low-fat and fat-free dairy products. A growing body of research suggests that dietary protein, specifically, can help promote satiety, facilitating weight loss when consumed as part of reduced energy diets.

Several clinical trials have specifically assessed the effects of high-quality protein from eggs on satiety and weight loss. For example:

  • In a study in overweight adults, calorie-restricted diets that included either eggs or a bagel for breakfast were compared; the people who consumed eggs for breakfast lowered their body mass index by 61%, lost 65% more weight, and reported feeling more energetic than those who ate a bagel for breakfast.
  • Men who consumed an egg breakfast versus a bagel breakfast showed that appetite hormones were suppressed following eggs at breakfast, as was energy intake over the course of the day.
  • A study of overweight premenopausal women that evaluated satiety responses to eating a turkey sausage and egg breakfast sandwich versus a low-protein pancake breakfast showed better appetite control and few calories consumed at lunch following the egg-based breakfast.
  • In a 3-month trial among subjects with type 2 diabetes, those who consumed 2 eggs per day for 6 days a week reported less hunger and greater satiety than those who consumed less than 2 eggs per week.

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Does Eating Smaller, Frequent Meals or Snacks of Nutrient Dense Foods Help Manage Weight?

Confusing nutrition messages are often linked to timing of meals and types of foods, but struggling consumers can take action by eating nutritious choices relatively more frequently and earlier in the day.

 Ghadeer Aljuraiban and research colleagues summarized cross-sectional associations between both the frequency and the time of eating, to energy density, nutrient quality (using the NRF9.3 index), and BMI, using data on 2,385 men and women age 40-59 years living in the US and the UK, participating in the International Study on Macro/Micronutrients and Blood Pressure (Aljuraiban, 2015). Note that “[o]nly solid foods were included in calculating energy density, consistent with previous studies that concluded that beverages should be excluded…” because liquids disproportionately affect energy density.

On average, women reported more eating occasions/day than men (5.0 compared to 4.6/day, respectively) and had a lower energy density (kcal/g). Women and men consumed a similar ratio of evening/morning energy intake (3.3 and 3.4 ratio of evening to morning on average).

Overall,

“[P]articipants who ate more frequently and consumed most of their energy earlier in the day (>6 eating occasions/24 hours and ratio of evening/morning energy intake <1.8) had lower energy density, total energy intake, and alcohol intake; higher NRF9.2 [i.e., higher nutrient rich food index], food weight, and fruit intake compared to those who ate fewer eating occasions…and consumed most of their food later in the day…”

BMI was inversely associated with eating occasions (i.e., the more occasions, the lower BMI) and with nutrient density (NRF9.3). As expected, BMI was positively associated with dietary energy density. It was also associated with higher ratio of evening/morning energy intake.

Also from this study, it appears that those eating more frequently, but earlier in the day, tend to eat more low-fat/fat-free dairy, cooked vegetables, and fruit (high nutrient dense foods) and less red meat and less beverages overall, but particularly alcohol.

To summarize, the authors concluded by stating

“Our findings demonstrated that lower BMI levels in more frequent eaters are associated with consumption of lower dietary energy density and higher nutrient quality foods. Modifying eating behavior through more frequent meals of low dietary energy density and high nutrient quality may be an important approach to control epidemic obesity.”

 

Reference Citation

GS Aljuraiban, Q Chan, LM Oude Griep, IJ Brown, ML Daviglus, J Stamler, L Van Horn, P Elliott, and GS Frost for the INTERMAP Research Group. “The impact of eating frequency and time of intake on nutrient quality and body mass index: The INTERMAP study, a population-based study” Journal of the Academy of Nutrition and Dietetics. 2015;Vol. 115(4):528-535.

 

Robyn Kievit Kirkman, FNP-BC, RDN, LDN, CSSD, CEDRD, is a dietitian in private practice in Boston & Concord, MA, and also works as a nurse practitioner. She serves as a health professional advisor to the Egg Nutrition Center.

 

Views expressed by the author may not be those of the Egg Nutrition Center.

Stock media provided by [TiramisuStudio]/Pond5.com

Physiological Impacts of Protein and Effects on Weight Management

ENC likes to provide the opportunity for up and coming investigators to showcase their research, and today’s post comes from a student of Jamie I. Baum, PhD, Assistant Professor of Nutrition at the University of Arkansas. Dallas Johnson is a graduate of the University of Arkansas receiving a B. S. in Biology. He now works as a research associate in Dr. Jamie Baum’s lab conducting projects focusing role of dietary protein on energy metabolism and metabolic health. Dallas has recently been accepted in to medical school and will be starting in the fall of 2015.

lab-scientist-stock-photoMore than one third of Americans are obese, making obesity a very real public health concern (1). Obesity comes with a multitude of health issues including cardiovascular disease, elevated risk of diabetes and metabolic syndrome. While individual situations can vary greatly, increasing protein levels in the diet has been shown to be an effective way to help combat obesity (2).

One of the ways protein can affect daily calorie intake is through its ability to increase satiety. Although high carbohydrate meals can increase satiety acutely, meals higher in protein (20-30% of the total energy provided by the meal) have been shown to have a more prolonged effect on satiety.  According to a study by Westerterp-Plantenga et al., published in the British Journal of Nutrition, this feeling of satiety is attributed to the ability of protein to stimulate the release of glucagon-like peptide-1 (GLP-1). Specifically, GLP-1 mediates the so-called “ileal brake”, an inhibitory feedback mechanism which controls the motility of a meal through the gastrointestinal system, and thus slows gastric emptying (3), thus leading to the feeling of being “full.” Moreover, free amino acids are released into the bloodstream following a high protein meal, which can also enhance the feeling of fullness (4).

In addition to inducing satiety, a high protein diet has also been found to impact the body’s daily energy expenditure. Daily energy expenditure can be broken down into different categories.  Active expenditure is the most variable form and results from physical activity. Resting metabolic ratecomprises around 70% of one’s daily calorie use and doesn’t vary much. One of the variants in resting metabolic rate is the total weight of lean tissue (e.g. muscle) in the body (4). Lean tissue can be increased or maintained by engaging in regular resistance exercise and a consistent intake of protein and calories in daily meals (4).

Protein not only has the potential to affect long-term energy expenditure but can also affect calories burned directly after a meal (diet-induced thermogenesis), even more so than other macronutrients (5). This increase in diet-induced thermogenesis is partly due to an enhanced protein turnover rate.  When the body is flooded with more protein than it can handle, it actively oxidizes and eliminates the excess amino acids. This leads to an increase in thermogenesis and the resultant up-regulation of uncoupled protein-2 (UCP2) in the liver and uncoupled protein-1 (UCP1) in brown adipose tissue, in turn, leads to higher energy expenditure (5).  Protein is also an inefficient source of ATP compared to fat and carbohydrate, requiring several stages of metabolism, including urea synthesis, before becoming available for energy production. According to a recent study, up to forty-two percent of the observed increase in energy expenditure following a high-protein, carbohydrate-free meal can be explained by these additional steps and the increase in gluconeogenesis that follows (4).

The battle against obesity is a very complex, multi-faceted issue that includes hormonal balance, genetic makeup and metabolic processes, but evidence from recent and ongoing studies suggests that protein can play an important role in body weight management.

 

References:

1. Ogden C. L., Carroll, M. D., Kit, B.K., & Flegal K. M. (2014). Prevalence of childhood and adult obesity in the United States, 2011-2012. Journal of the American Medical Association, 311(8), 806-814.

2. Rodriguez, N., & Garlick, P. (2008). Introduction to protein summit 2007: Exploring the impact of high-quality protein on optimal health. The American Journal of Clinical Nutrition, 87, 1551-3.

3. Marathe CS, Rayner CK, Jones KL, Horowitz M. Effects of GLP-1 and incretin-based therapies on gastrointestinal motor function. Exp Diabetes Res. 2011;2011:279530.

4. Westerterp-Plantenga, M., Lemmens, S., & Westerterp, K. (2012). Dietary protein- its role in satiety energetics, weight loss and health. British Journal of Nutrition, 108, S105-S112.

5. Paddon-Jones, D., Matters, R., Wolfe, R., Astrup, A., & Westerterp-Plantenga, M. (2008). Protein, weight management, and satiety. The American Journal of Clinical Nutrition, 87.

ENC at FNCE 2014

 Almost a month has passed since the 2014 Academy of Nutrition & Dietetics’ Food & Nutrition Conference & Expo (FNCE®), the world’s largest gathering of registered dietitian nutritionists (RDNs), held on October 18-21 in Atlanta, GA, and the month after gives practitioners time to digest what they’ve learned and put it into practice. As a registered dietitian nutritionist, I enjoyed seeing the emerging science, food, and practice come together, helping practitioners to think outside the box and coming away with evidence-based, yet practical tips for their clients.

ENC team members had the opportunity to share credible science and practical nutrition solutions with members of the Academy by sponsoring the Weight Management Dietetic Practice Group (WM DPG) member breakfast, featuring an educational session and a breakfast for WM DPG members and other invited DPGs including Healthy Aging, Diabetes Care and Education, Nutrition Education for the Public, Women’s Health and Medical Nutrition Practice Group. The educational session featured a presentation on the “Strategic Use of Protein Quality and Quantity to Enhance Satiety and Weight Management,” by Nikhil Dhurandhar, PhD, Professor at Pennington Biomedical Research Center and President-Elect of The Obesity Society.

Dr. Dhurandhar provided an overview of a series of studies that have testing the satiating properties of a number of different protein sources under acute conditions, and suggest a distinct satiating property of high-quality protein sources, such as eggs, that may promote body weight management. Aimed at providing advice on how to help their clients manage weight effectively with protein, Dr. Dhurandhar reminded the audience that obesity is not caused by just eating one big meal, nor is it combatted by just one small meal, and that long term voluntary control of food intake to treat or prevent obesity is highly challenging. Thus, one strategy may be to harness the satiating properties of foods, particularly protein.

Current evidence shows that that the satiating effect of proteins can be maximized by including protein as part of a reduced-energy diet for weight loss.1 Including a high-quality protein source at the breakfast meal may promote satiety during the day, increase dietary adherence, and enhance weight loss.2,3 His current evidence suggests that the quality of the protein may enhance its satiating effect without a significant increase in the amount of food/calories consumed. In addition, his studies have demonstrated that a breakfast containing eggs may enhance weight loss by prolonging satiety, decreasing energy intake and reducing body weight and waist circumference.4-6

FNCE-placemat

To help attendees translate the science provided by Dr. Dhurandhar, we created a handout summarizing the session.

See everyone next year in Nashville, TN.

 
 

 
 
References

  1. Layman DK. Protein quantity and quality at levels above RDA improves adult weight loss. J Am Coll Nutr 2004; 23(6):631S-636S.
  2. Layman DK. Dietary Guidelines should reflect new understandings about adult protein needs. Nutr Metab (Lond). 2009 Mar 13;6:12. doi: 10.1186/1743-7075-6-12.
  3. Leidy HJ, Ortinau LC, Douglas SM, Hoertel HA. Beneficial effects of a higher-protein breakfast on the appetitive, hormonal, and neural signals controlling energy intake regulation in overweight/obese, “breakfast-skipping,” late-adolescent girls. Am J Clin Nutr. 2013 Apr;97(4):677-88.
  4. Vander Wal JS, Marth JM, Khosla P, Jen KL, Dhurandhar NV. Short-term effect of eggs on satiety in overweight and obese subjects. J Am Coll Nutr. 2005;24(6):510-5.
  5. Vander Wal JS, Gupta A, Khosla P, Dhurandhar NV. Egg breakfast enhances weight loss. Int J Obes (Lond). 2008;32(10):1545-51.
  6. Bayham BE, Greenway FL, Johnson WD, Dhurandhar NV. A randomized trial to manipulate the quality instead of quantity of dietary proteins to influence the markers of satiety. J Diabetes Complications. 2014; E-pub ahead of print.

Complexity of Individual Variability in Nutrition

close-up-summer-2014-tnToday’s post comes from the Summer Issue of the Nutrition Close-Up, ENC’s newsletter that provides information on current nutrition and research trends and upcoming presentations. Please visit eggnutritioncenter.org to access the current and previous issues of the Nutrition Close-Up.

One size does not fit all when it comes to health. Be it diet, exercise, or prescription medications, what works wonderfully for one person may produce little effect or even the opposite effect in others. This is not surprising given metabolic differences between individuals. I remember observing this first-hand as an undergraduate student in a clinical chemistry course. Each student underwent some basic blood tests, and we compared results across the class. For some tests (e.g., liver enzymes), there was little variability among the students. But in others, there was quite a bit of diversity in results. For example, the blood glucose and insulin responses to an oral glucose tolerance test varied dramatically student to student. The athletic students in the class barely saw much rise in glucose, whereas several of the overweight students saw a dip in glucose below baseline in the late postprandial period (often called reactive hypoglycemia).

In conducting human nutrition intervention trials, I have gained an even greater appreciation for the inter-individual variability that occurs in response to diet and lifestyle interventions. However, this variability is often overlooked or unexplored. Mots scientific papers only report means for the subject population. The standard deviation of the mean can provide some insight into the variance of the dataset, but it does not provide descriptive information, such as the percent of the subject population that responded to a particular treatment. Yet in some cases, inter-individual variability may be important to our understanding of human health.

For example, there is a growing appreciation for understanding inter-individual variability with respect to achieving and maintaining an optimal body weight (i.e., specific genes, environmental factors, epigenetic effects, etc.). McClain et al. recently reported that women with insulin resistance were less successful in adhering to a low-fat weight loss diet and therefore, less likely to lose weight compared to those following a low-carbohydrate diet (1). The investigators hypothesize that higher carbohydrate intakes as part of a low-fat diet negatively influence glucose homeostasis, leading to greater levels of hunger. In an environment where highly palatable food is pervasive, it is easy to quell hunger the minute the urge strikes, compromising diet adherence.

In recent years, the gut microbiome has emerged as another factor that influences responses to diet and lifestyle factors, likely contributing to inter-individual variability in nutrition studies. There is a growing body of evidence that the diversity of bacteria within the gut microbiome is particularly important (2). For example, Santacruz et al. showed greater weight loss in a subset of individuals who showed more marked alterations in the diversity of gut microbiota in response to a calorie-restricted diet (3). Whether there are specific diet-microbiome relationships that further influence weight loss, as well as alter other aspects of physiology, remains to be determined. But based on the research to date, it seems highly likely that we are only beginning to understand the complex set of factors that not only make us who we are, but influence our responses to our environment, including diet.

If there is a theme in this issue of Nutrition Close-Up, it is this concept of “one size does not fit all” when it comes to nutrition. Differences between people, whether on a macro level (e.g., age, race, athletic status, dietary preferences, culture, etc.) or micro level (e.g., genetics, diversity of the gut microbiota, etc.), influence responses to diet. Given the increasing complexity of such differences, it may be decades before research provides solutions to prevent and manage chronic disease. In the near term, keeping abreast and appreciating such differences may be the best we can do.

 

References:

  1. McClain AD, Otten JJ, Hekler EB, Gardner CD. Adherence to a low-fat vs. low-carbohydrate diet differs by insulin resistance status. Diabetes Obes Metab. 2013; 15:87-90.
  2. Erejuwa OO, Sulaiman SA, Ab Wahab MS. Modulation of gut microbiota in the management of metabolic disorders: the prospects and challenges. Int J Mol Sci. 2014; 15:4158-88.
  3. Santacruz A, Marcos A, Warnberg J, Marti A, Martin-Matilas M, Campoy C, Moreno LA, Veiga O, Redondo-Figuero C, Garagorri JM, Azcona C, Delgado M, Garcia-Fuentes M, Collado MC, Sanz Y; EVASYON Study Group. Interplay between weight loss and gut microbiota composition in overweight adolescents. Obesity (Silver Spring). 2009; 17:1906-15.

Two Things You Didn’t Know About Dietary Protein

T-Rains-headshotAfter years of standing in the shadows of carbohydrate and fat research, there’s been an influx of publications in recent years on the benefits of dietary protein. Much of this new science has focused on satiety and preservation of lean mass and how these characteristics facilitate weight loss. Protein, particularly at the expense of carbohydrate, has also been consistently shown to reduce risk for high blood pressure.1 But researchers have now begun exploring the impact of protein on endpoints beyond body composition, weight management, and vascular health, revealing some new and interesting benefits of dietary protein.

Researchers at the University of Missouri recently published results from a randomized, controlled crossover study which compared appetite, satiety, and evening snacking in adolescent girls who consumed either a normal-protein breakfast (13 g), high-protein breakfast (35g), or no breakfast.  Results of the primary outcomes were published last year, and showed that the high-protein breakfast elicited greater feelings of fullness than the normal-protein breakfast.  Further, only the high protein breakfast reduced evening snacking of high-fat foods, a finding that had not been previously explored.2

In late August, Hoertel and collaborators published additional findings from this main study, evaluating food cravings and homovanillic acid (HVA), a metabolite of dopamine.3 [Dopamine is a neurotransmitter associated with motivation, reward, and well-being.  Because dopamine is unable to leave the brain, HVA is typically measured as a surrogate since it correlates with dopamine activity in the brain.]

Results showed that while both the normal- and high-protein breakfasts reduced cravings for savory foods compared to no breakfast, the response was much greater for the high protein breakfast.  In addition, levels of HVA were higher for the high-protein breakfast, suggesting that participants found the higher protein breakfast more rewarding.  How it produces this effect remains to be determined.  One hypothesis presented by the investigators is that increased protein leads to higher concentrations of the amino acid, tyrosine, a precursor to dopamine.  Additional research is needed to better understand the mechanisms involved.

The bottom line is that the benefits of a protein-rich meal for breakfast may extend beyond fullness, impacting food cravings later in the day and substances in the brain that promote feelings of well-being.  Only time will tell what other benefits of protein remain to be discovered.

References:

  1. Buendia JR, Bradlee ML, Singer MR, Moore LL. Diets Higher in Protein Predict Lower High Blood Pressure Risk in Framingham Offspring Study Adults. Am J Hypertens. 2014 Sep 6. [Epub ahead of print]
  2. Leidy HJ, Ortinau LC, Douglas SM, Hoertel HA. Beneficial effects of a higher-protein breakfast on the appetitive, hormonal, and neural signals controlling energy intake regulation in overweight/obese, “breakfast-skipping,” late-adolescent girls. Am J Clin Nutr. 2013 Apr;97(4):677-88.
  3. Hoertel HA, Will MJ, Leidy HJ. A randomized crossover, pilot study examining the effects of a normal protein vs. high protein breakfast on food cravings and reward signals in overweight/obese “breakfast skipping”, late-adolescent girls. Nutr J. 2014 Aug 6;13:80.