Last week we sent out a People’s Pharmacy Special Health Alert. It was titled “Low-Carb Diet Wins Diet Wars…Again!” We knew that there would be a lot of health reports on this latest research. We wanted you to have immediate access to the original study and get our interpretation of the results. Diet recommendations are among the most contentious and confusing areas of health policy today. Not surprisingly, the latest low-carb diet research has provoked a great deal of reader backlash. You will discover that people get very upset if data contradict their beliefs.
What the Researchers Did:
For decades, nutrition experts have been claiming that a calorie is a calorie, no matter what food provides it. A well-done study in the BMJ (Nov. 14, 2018) has just thrown the dogma that all calories are equal into question.
The researchers recruited 164 overweight individuals from Framingham, Massachusetts, who had just lost 12 percent of their body weight on a low-calorie diet supplied by the researchers. They provided these volunteers with their meals, with the calories adjusted to maintain that weight loss.
A Randomized Trial:
Participants were randomly assigned to take meals with 60 percent, 40 percent or 20 percent of their calories from carbohydrate sources. Protein was held constant at 20 percent of calories in all three experimental diets. Fat varied depending upon carb intake. If someone was getting 20 percent of calories from carbohydrates (the low-carb diet) fat had to be 60 percent. Conversely, if a volunteer was on the high-carb diet, fat intake would be 20 percent.
Where the Food Came From:
The investigators arranged for all the meals to be provided, thus bypassing individual variations that occur when people fend for themselves. They assessed energy expenditure very accurately using radioactive labeled water.
The Envelope Please!
By the end of the five-month trial, people in the low-carb diet group were using significantly more energy than those in the high-carb diet group. The difference came out to approximately 250 calories a day. If a person used 250 calories more than they ate every day, they could potentially lose more than 20 pounds in three years.
The researchers report that the energy expenditure on the low-carb diet was highest for those who had high insulin levels when the study began. The hormones ghrelin and leptin, which regulate hunger and fat storage, were also lower among the individuals on the low-carb regimen.
One of the principal investigators, David Ludwig, MD, PhD, explained the team’s research in the L.A. Times (Nov.14, 2018).
“Participants in the low (20%) carbohydrate group burned on average about 250 calories a day more than those in the high (60%) carbohydrate group, just as predicted by the carbohydrate-insulin model. Without intervention (that is, if we hadn’t adjusted the amount of food to prevent weight change), that difference would produce substantial weight loss — about 20 pounds after a few years. If a low-carbohydrate diet also curbs hunger and food intake (as other studies suggest it can), the effect could be even greater.”
These results offer hope that a strict low-carb diet could help increase energy expenditure and potentially help people trying to lose weight.
BMJ, Nov. 14, 2018
We were a bit surprised at the reader reaction to this study. After all, this was well-conducted research. Such a feeding study is a rarity. Here is how Dr. Ludwig explains the protocol:
“For our clinical trial — one of the largest feeding studies ever conducted — we collaborated with Framingham State University and the company that manages its food service. We recruited 164 students, faculty, staff and community members who agreed to eat only what the study dictated for a full academic year.”
As we described in our original summary of the research, this kind of feeding study is unusual. Many of the other studies that are so frequently quoted in books and the media are epidemiological or observational studies. They are far less reliable than an actual feeding study where food intake is carefully controlled and energy expenditure carefully monitored.
Readers Offer Their Perspective:
William R. is a low-carb diet skeptic:
“The study did NOT show that a low-carb diet helps you lose weight; It showed that low carb diets increase your metabolic rate. The weight loss implications are only speculative, not proven.
“In fact, most studies have shown that a low-carb diet does little to help you lose weight, unless the diet also makes you eat less. By the way , the authors state that their study suggests, but does not prove that the diet could help you lose 20 pounds ‘in a few years.’ So let’s say the few years is 6 years. That means you would lose 20/6 or 3.3 pounds a year. If you think this is the answer to obesity, you need to think again.
“Losing weight requires eating fewer calories or exercising more. If a low-carb diet enables you to eat fewer calories, then go for it.”
We have heard from many low-fat advocates. They are enthusiastic followers of Dean Ornish and T. Colin Campbell.
Mary in Washington shares her perspective:
“The diet that has worked for me for many, many years is a vegan whole foods, plant based diet with small amounts of fat and sugar. It is essentially the diet recommended in the film and book, “Forks Over Knives,” by Drs. Dean Ornish, Caldwell Esselstyn, John and McDougall, and by T. Colin Campbell, Ph.D., author of the China Study. This diet helps me stay healthy and active at 70+, and it’s been documented to reverse obesity, heart disease, Type 2 diabetes, and other lifestyle diseases.”
Jane eats “tons of carbs” and doesn’t get the new research:
“Before I had open heart surgery I had a test to see how my arteries were and they were wide open. My problem was a valve problem. The cardiologists doing the test said to me, ‘we can tell that you have watched your fats over the years because you have no blockages and will not need any by-passes during the surgery. We will only deal with the valve issue.”
“I eat tons of carbohydrates. I read all food labels. When I see there is a fat content of more than just a few grams, I don’t purchase that product.”
“So, what’s the story? Now I’m to eat fat and skip carbohydrates? By the way, my weight is low and became low when I began eating low-fat foods. I don’t understand.”
The Other Side of the Low-Carb Diet Story:
Jade has a different story regarding the low-carb diet approach:
“I was introduced to a low-carb diet by a friend who had lost 40 pounds in 6 months. It was a plan provided through her health provider. Basically it was a ‘keto’ style approach that provided a list of ‘allowed’ foods – lots of veggies, and proteins (emphasizing eggs and fish over meats). That appealed to me because I didn’t have to keep track of anything and it fit with my ‘on and off again vegetarian’ philosophy.
“So far I’ve lost 13 pounds and 3-4 inches off thighs, midriff and belly. It feels weird at first to emphasize even good fats. It’s amazing how ‘programmed’ we all are against a high-fat diet! I’ve been following the latest research which concurs that sugar, not fat, is the true enemy here.”
Judy shares a somewhat similar experience:
“I’ve followed a low-carb diet with varying amounts of fruit (depending on if I’m trying to lose weight) since the Atkins diet came out in the 1970s. My primary care physician (an internist) stated that “a low-carb diet will cure type 2 diabetes.” He emphasized the word cure. At 70, I’m active, still working, and take no prescription medications (but quite a few supplements.) This study is consistent with my experience.”
Melanie in North Carolina adds this story:
“I am so glad the research continues and shows positive results. I am a believer.
“Four years ago, my blood sugar tested high and I got the ‘speech’ from my doctor. He wanted to put me on metformin then, but I said no – – what could I do to change my blood sugar levels?
“That’s when I began to thoroughly study the low-carb diet way of life and how it could help. I am proud to say, that I’ve lost 30 pounds and am on no medication. My blood sugar is very stable and my A1C is awesome!
“YEAH ME! Keep spreading the word.”
Harvey in Ohio notes that the intermittent fasting approach of Dr. Jason Fung also helps:
“I am pleased to see The Peoples Pharmacy so quickly covered this new research. It is elegant.
“I am also extremely happy to see that Jason Fung is a featured guest on your radio show this week. All this ties together.
“Dr. Fung’s Intermittent fasting results in ketosis. A low-carb, high-fat diet (LCHF) also results in ketosis. When combined, the effect is magnified. There is rapid weight loss. I have been doing both for three months with rapid weight loss. I am feeling fabulous. It reduces inflammation drastically. That helps many conditions including arthritis and autoimmune disorders. I have no soreness after heavy workouts!”
You can listen to our interview with Dr. Jason Fung at this link.
You can listen to the free audio stream by clicking on the green arrow above Dr. Fung’s photograph. You can also download the FREE mp3 file by clicking on the download mp3 at the bottom of the page. Make sure you toggle the MP3 version by clicking on the downward arrow unless you would like a CD to share with family and friends.
There are LOTS more comments about our original report on the low-carb diet research published in the BMJ at this link. We suspect you will find them quite revealing. When you get to the bottom of the page you will see a box with “older comments.” Click to see all 54 comments.
We are agnostic on the best dietary pattern for any given individual. We had the opportunity to interview Dr. Christopher Gardner about his DIETFITS study published in JAMA on February 20, 2018. Dr. Gardner points out that some people do really well on the low-carb diet while others do really well on the low-fat diet. We think you will find this interview equally informative.
Add your own thoughts about the low-carb diet approach in the comment section below.