Currently browsing posts about: Diets

Yesterday I explained why “butter is back” is not useful dietary advice, even when studies show that eating butter has little or no effect on disease risk (the total diet and calories are what matter).  Now I can say the same thing about low-carbohydrate diets.

The debate about whether fat or carbohydrate is responsible for obesity has passionate advocates on both sides, although those for carbohydrates predominate in the press these days.

As explained by Julia Belluz of Vox,

The main scientific model behind the low-carb approach is the “carbohydrate-insulin hypothesis,” which journalist Gary Taubes, Harvard professor David Ludwig, and others have extensively promoted. It suggests that a diet heavy in carbohydrates (especially refined grains and sugars) leads to weight gain because of a specific mechanism: Carbs drive up insulin in the body, causing the body to hold on to fat and suppress calorie burn.

According to this hypothesis, to lose weight you reduce the amount of carb calories you eat and replace them with fat calories. This is supposed to drive down insulin levels, boost calorie burn, and help fat melt away…instead of just cutting calories, you’re supposed to change the kinds of calories in your diet to lose weight.

To his great credit, Gary Taubes was willing to put this hypothesis to the test.  He organized the Nutrition Science Initiative (NuSI) to fund studies that he must have hoped would demonstrate the benefits of low-carb diets.

To its great credit, NuSI recruited highly experienced and respected obesity investigators to design and conduct the studies.

The first of these studies has just been published.   It fully discloses the role of NuSI.

Supported by the Nutrition Sciences Initiative…Nutrition Sciences Initiative (NuSI) convened the research team, helped formulate the hypothesis, and provided partial funding. NuSI and its scientific advisors were given the opportunity to comment on the study design and the manuscript, but the investigators retained full editorial control.

In this case, because I am familiar with the work of some of the investigators, I’m inclined to take these statements at face value.

Here’s what they did.  They put 17 overweight or obese men in a metabolic ward and fed them a very low carbohydrate diet, so low that it would induce fat breakdown and ketosis.  The calories were supposed to be sufficient to maintain weight, but were not.  The men lost weight from water excretion and breakdown of body protein as well as of fat, as is typical of what happens during partial starvation.  Energy expenditure did not increase to the level anticipated from the carbohydrate-insulin model.

The Abstract concluded:

The isocaloric KD [ketogenic, very low carbohydrate diet] was not accompanied by increased body fat loss but was associated with relatively small increases in EE [energy expenditure] that were near the limits of detection [translation: barely detectable] with the use of state-of-the-art technology.

The Discussion concluded:

Therefore, our data do not support the carbohydrate–insulin model predictions of physiologically relevant increases in EE or greater body fat loss in response to an isocaloric KD. However, it is possible that dietary carbohydrate restriction might result in decreased ad libitum energy intake—a prediction of the carbohydrate-insulin model that was not tested in the current study but deserves further investigation.

In other words, restricting carbohydrate does not increase body fat loss or energy expenditure but might help you eat fewer calories.

This result confirms some of the results of a previous study from the first NuSI author. That one, funded by NIH, concluded:

Whereas carbohydrate restriction led to sustained increases in fat oxidation and loss of 53 ± 6 g/day of body fat, fat oxidation was unchanged by fat restriction, leading to 89 ± 6 g/day of fat loss, and was significantly greater than carbohydrate restriction (p = 0.002).

Taken together, these studies show that both low-carbohydrate and low-fat diets cause weight loss when calories are restricted, but low-fat diets cause greater losses in body fat content than do low-carbohydrate diets.

In my book with Malden Nesheim, Why Calories Count: From Science to Politics, we review a 1964 study that put obese patients in a metabolic ward and fed them low-calorie diets of widely varied composition.  They lost weight at the same rate on diets ranging from 3% to 60% carbohydrate and from 13% to 83% fat.  They titled the study “Calories Do Count.”  The NuSI studies confirm the benefits of reducing calories from any source to lose weight.

Bottom line:

• With regard to weight loss, calories count and the relative proportions of fat, protein, and carbohydrate do not matter much (although low-carb diets may help with eating less).
• With regard to health, the food sources of calories matter very much indeed, and nearly everyone would be better off eating less sugar—at the very least because sugars provide calories, but no nutrients.

*Note: this version corrects an error in the version originally posted.  Hall et al.’s 2015 study was funded by NIH, not NuSI.  Apologies.

I’ve just received a new report from USDA’s Economic Research Service, U.S. Food Commodity Consumption Broken Down by Demographics.  This looks at trends in per capita food availability—the amounts of specific foods available in the food supply, obtained from data on production and imports, from 1994 to 2008, corrected for waste, per person in the United States.

Food availability data, especially when corrected for waste, suggest trends in per capita consumption patterns (otherwise why would USDA bother to collect them?), but they are not consumption data.  They are about supply, not use.

With that said, the trends seem odd to me.  They demonstrate a decline in the availability of:

• Fruit (mainly oranges)
• Vegetables
• Dairy (mainly milk)
• Beef
• Pork
• Potatoes
• Sugars

The supply of yogurt and cheese, however, has increased (but their per capita availability is relatively low).

The supply of apple juice also has increased:

Food availability data corrected for waste are supposed to come close to what people actually eat.  But if people are eating less of practically all foods, how come so many of us are still gaining weight?  Surely it’s not because of apple juice.

These data are an important source of information on U.S. dietary patterns.

But what do they mean?  The authors do not say, so it’s left to us to figure that out.

As I keep saying, finding out what people eat is the single most intellectually challenging problem in the field of nutrition.

Food-Navigator USA publishes occasional “special editions” with collections of articles on similar topics.  This one is on how food companies are dealing with weight management: “With almost two thirds of Americans overweight or obese, weight management is still a huge market opportunity for food and beverage manufacturers. However, messaging is moving away from diet-based concepts to more positive messages about food quality, satiety, and overall health & wellness.”

•  Back to Nature Foods Co. repositions SnackWell’s as a “free-from” line: Back to Nature Foods Co.’s revitalization of the recently acquired iconic SnackWell’s brand is an example of how established companies can refresh aging brands that are struggling to better compete with new products from disruptive startups… Watch now

A nutrient profiling system for the (re)formulation of a global food and beverage portfolio.  Antonis Vlassopoulos · Gabriel Masset · Veronique Rheiner Charles ·Cassandra Hoover · Caroline Chesneau‑Guillemont · Fabienne Leroy ·Undine Lehmann · Jörg Spieldenner · E‑Siong Tee · Mike Gibney ·Adam Drewnowski.  Eur J Nutr DOI 0.1007/s00394-016-1161-9.

• Conclusions:  The NNPS sets feasible and yet challenging targets for public health-oriented reformulation of a varied product portfolio; its application was associated with improved nutrient density in eight major food categories in the USA and France.
• Funding: The research presented herein was funded by Nestec Ltd, which is a wholly owned affiliate of Nestlé S.A.  The first eight authors are employed by Nestlé.
• Comment: the paper is the basis of a Nestlé infographic.

Including whey protein and whey permeate in ready-to-use supplementary food improves recovery rates in children with moderate acute malnutrition: a randomized, double-blind clinical trial.  Heather C Stobaugh, Kelsey N Ryan, Julie A Kennedy, Jennifer B Grise, Audrey H Crocker, Chrissie Thakwalakwa, Patricia E Litkowski, Kenneth M Maleta, Mark J Manary, and Indi Trehan.  Am J Clin Nutr  First published February 10, 2016, doi: 10.3945/​ajcn.115.124636.

• Conclusion: This study highlights the importance of milk protein in the treatment of MAM, because the use of a novel whey RUSF resulted in higher recovery rates and improved growth than did soy RUSF [ready-to-use supplemental food], although the whey RUSF supplement provided less total protein and energy than the soy RUSF.
• Funding for this project was provided by the Danish Dairy Research Foundation, Arla Foods Ingredients Group P/S, and the US Dairy Export Council. IT was supported by the Children’s Discovery Institute of Washington University in St. Louis and St. Louis Children’s Hospital…The funders had no role in the design or implementation of the study and no role in the analysis or interpretation of the data.

Oral health promotion: the economic benefits to the NHS of increased use of sugarfree gum in the UK.  L. Claxton, M. Taylor & E. Kay.  British Dental Journal 220, 121 – 127 (2016).  Published online: 12 February 2016 | doi:10.1038/sj.bdj.2016.94

• Conclusion If all members of the UK 12-year-old population chewed SFG frequently (twice a day), the potential cost savings for the cohort over the course of one year were estimated to range from £1.2 to £3.3 million and if they chewed three times a day, £8.2 million could be saved each year…This study shows that if levels of SFG usage in the teenage population in the UK could be increased, substantial cost savings might be achieved.
• Declaration: This study and writing support for the manuscript were funded by Wrigley Oral Healthcare Programme.

Dietary carbohydrate restriction as the first approach in diabetes management: Critical review and evidence base Richard D. Feinman, Wendy K. Pogozelski , Arne Astrup M.D., Richard K. Bernstein M.D., Eugene J. Fine M.S., M.D. , Eric C. Westman M.D., M.H.S.  , Anthony Accurso M.D. , Lynda Frassetto M.D.  , Barbara A. Gower Ph.D.  , Samy I. McFarlane M.D.  , Jörgen Vesti Nielsen M.D.  , Thure Krarup M.D. , Laura Saslow Ph.D. , Karl S. Roth M.D. , Mary C. Vernon M.D. , Jeff S. Volek R.D., Ph.D. , Gilbert B. Wilshire M.D. , Annika Dahlqvist M.D.r , Ralf Sundberg M.D., Ph.D.  , Ann Childers M.D.  , Katharine Morrison M.R.C.G.P.  , Anssi H. Manninen M.H.S.  , Hussain M. Dashti M.D., Ph.D., F.A.C.S.,  F.I.C.S., Richard J. Wood Ph.D., Jay Wortman M.D. , Nicolai Worm Ph.D.  Nutrition. January 2015 Volume 31, Issue 1, Pages 1–13 DOI: http://dx.doi.org/10.1016/j.nut.2014.06.011

• Conclusion: Here we present 12 points of evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1.
• Disclosure: AA is consultant/member of advisory boards for the Dutch Beer Knowledge Institute, NL, Global Dairy Platform, USA, Jenny Craig, USA, McCain Foods Limited, USA, McDonald’s, USA, and Gerson Lehrman Group, USA (ad hoc consultant for clients). He is recipient of honoraria and travel grants as speaker for a wide range of Danish and international concerns. He has conducted research funded by a number of organizations with interests in the food production and marketing sector. RDF writes reviews for Fleishman-Hillard, whose client is the Corn Refiners Association and he has received grant support from the Veronica and Robert C. Atkins Foundation. EJF has received grant support from the Veronica and Robert C. Atkins Foundation. TK sits on an advisory board for Eli Lilly and gives lectures for Lilly about the diabetic diet. NW has written popular-audience books on low-carbohydrate diets and is a consultant and promoter for Leberfasten/Hepafast, a specific low-carbohydrate meal replacement program. JW is on the Scientific Advisory Board of Atkins Nutritionals Inc. with paid retainer, honoraria, and travel costs. None of the other authors have anything to declare.
• Comment: The Atkins Diet is low-carbohydrate.

Comparison of Commercial and Self-Initiated Weight Loss Programs in People With Prediabetes: A Randomized Control Trial David G. Marrero, PhD, Kelly N. B. Palmer, MHS, Erin O. Phillips, BA, Karen Miller-Kovach, EBMA, MS, Gary D. Foster, PhD, and Chandan K. Saha, PhD. Am J Public Health. Published online ahead of print February 18, 2016: e1–e8. doi:10.2105/AJPH.2015.303035

• Conclusions. A large weight-management program is effective for achieving lifestyle changes associated with diabetes prevention. Such programs could significantly increase the availability of diabetes prevention programs worldwide making an immediate and significant public health impact.
• Funding: This study was funded by Weight Watchers International.

It’s close to a year since I first started collecting these studies.  When the year is up, I will do some analysis.  Until then, the bottom line is that it’s easier to find industry-funded studies with results favorable to the sponsor than it is to find those that are not.

Thanks to Andy Bellatti for noticing this at his local Las Vegas Whole Foods.

This reminds me so much of the Low-Carb craze way back in 2005.

Oh well.  Whatever works.

The Wall Street Journal, hoping to generate some controversy, got me involved in a point/counterpoint about the Paleo Diet: “Is a Paleo diet healthy?”

It can be, but this is a point/counterpoint.  Hence, I took the position “NO: You Lose Too Much Pleasure for Dubious Benefits.”  

Here’s what I said:

Nutritionist that I am, the first questions I have about any diet are: What is it? Is the rationale behind it logical? And does it promote health?

A paleo diet is based on the premise that our genes govern what’s best for us to eat. We evolved to eat whatever could be hunted or gathered. This makes it OK to eat leaves, shoots, roots, seeds, eggs, animals, birds and fish, but not OK to eat grains, legumes, dairy or processed foods.

Why do paleo proponents think the ills of modern society stem from a mismatch between our genetics and today’s typical diets? The cave men, some argue, didn’t suffer from diseases such as obesity, heart disease and diabetes.

The problem with that theory is that we really don’t know what our Paleolithic ancestors ate. As I often argue, determining what people eat is the single most intellectually challenging question in nutrition science. It is extraordinarily difficult to get an accurate idea of what people ate yesterday, let alone 10,000 to a million or more years ago.

In reality, scientists are nowhere near being able to match genes to specific kinds of diets. The reason cave men didn’t have chronic diseases like diabetes is more likely because they didn’t live long enough and lacked antibiotics, rather than because they didn’t eat carbohydrates.

Variety is key

What we know for sure is that the fundamental tenets of nutrition are variety, balance and moderation. The fewer kinds of foods consumed, the greater the chance of nutrient deficiencies. So while it is certainly possible to eat healthfully on a paleo diet, restricting whole groups of relatively unprocessed foods can make this more challenging. It also can take some of the joy out of eating by forcing people to give up foods that they love or that are part of their cultural heritage.

While there is no doubt that highly processed “junk” foods are unhealthy and should be kept to a minimum, grains and legumes are hardly the enemy. Diets that vary enormously—from the traditional high carbohydrate, rice-based cuisines of Asia to those of the Mediterranean rich in grains and olive oil—have been shown to promote health and longevity.

Yes, grains contain glutens, and bread and pasta are caloric, but such foods are also delicious and part of traditional diets in nearly every culture. Yes, legumes contain unpleasant phytochemicals, but these are mostly destroyed by cooking, and beans and peas are excellent sources of vegetable protein. If you eat foods from animal sources, why restrict dairy? Cheese and yogurt are lovely foods, and I, for one, cannot imagine life without an occasional serving of ice cream.

Eating less works

Any restrictive diet helps to reduce calorie intake, so it isn’t surprising that there are studies linking paleo to weight loss, lower blood sugar and a reduced risk of cancers for which obesity is a risk factor. Eating less works every time.

So does eating a largely plant-based diet. Research suggests that we can reduce risks for today’s diseases of affluence by eating more foods from plant sources and balancing calorie intake with expenditure. To the extent the paleo diet achieves these goals, it is a reasonable choice.

But food is so much more than bundles of nutrients. What we eat also nourishes us psychologically and culturally. So while a paleo diet isn’t necessarily bad, why bother? I’d be sad to miss all those delicious forbidden foods.

A reader who prefers his name to go unmentioned writes this in response to yesterday’s post about low-carb v. low-fat diets:

Hi Marion,

It is pretty simple.

1. Calories in, Calories out!

2.  Eat less. I cut out beer and ice cream.

3.  Get a Labrador retriever and walk everyday. If you don’t the dog will drive you crazy and probably destroy your house.

I got my first Lab in 2002 and weighed 240.  I am on my second Lab and now continue to weigh about 210 after having lost 35 pounds by 2006, and have crept up about 5 pounds.

It ain’t complicated!

He could make a fortune.  Just think: the “Get a Lab” diet—a guaranteed success!

To my great surprise, a new clinical trial finding that low-carbohydrate diets help people lose weight has been getting a lot of press. Its conclusion:

The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors.

This is news?

The trial, conducted by authors who previously published a meta-analysis that came to the same conclusion, told people to eat either a low-carbohydrate diet of less than 40 grams a day (the amount of sugar in one 12-ounce soda) or a “low-fat” diet of 30% of calories from fat or less.

They didn’t do either, of course (for one critic’s analysis, see examine.com).

I put quotes around “low-fat” because 30% of calories is not exactly what I would call low—lower, for sure, but not low. After a year, the low-carb dieters lost about 3.5 kg more than did the “low-fat” dieters.  They also showed greater improvements in their risk factors for cardiovascular disease.

As I told Andy Bellatti

The folks eating the low carbohydrate diet…were eating less, and probably a lot less.  It’s easier for some people to lose weight if they cut out whole categories of food, in this case, carbohydrates.  But is this a long-term solution?  For that, we need to see results for several years.   Studies that examine the effects of different kinds of diets—and there have been many—typically find that all work to the extent that they cut calories, but that people have trouble sticking to extreme diets, which the low-carb one was in this study.  Personally, I like carbs and would rather cut my calories some other way, but that’s just me.  The bottom line: if you want to lose weight and are having trouble doing it, you need to eat less.

This profoundly boring conclusion, discussed at length in my book with Malden Nesheim, Why Calories Count: From Science to Politics, has just been confirmed by yet another meta-analysis.  This one doesn’t seem to be getting much press, however.

It reports significant weight loss with any low-carbohydrate or low-fat diet.

Weight loss differences between individual named diets were small. This supports the practice of recommending any diet that a patient will adhere to in order to lose weight.

An accompanying editoria,  “A Diet by Any Other Name Is Still About Energy,” points out that study investigators only rarely analyze for how well participants in these studies actually adhere to the different diets, and for how long.

This makes it impossible for readers to figure out whether the weight loss was due to the specific components excluded from the diet or to the level of adherence.

In other words, whatever helps you eat less, helps you lose weight.  Go for it.