Low carb diet may help improve ‘bad’ cholesterol
- People with type 2 diabetes are at a higher risk of developing high cholesterol, which is a risk factor for heart disease.
- Traditionally, a high carbohydrate and low fat diet was considered best for people with type 2 diabetes.
- Over the past few years, some studies have shown that following a low-carbohydrate, high-fat diet may be beneficial for those with type 2 diabetes.
- A new study says that replacing some dietary carbohydrates with protein and fat in the diet of people with type 2 diabetes may help improve their cholesterol levels.
Previous studies also show that those with type 2 diabetes have a heightened risk of developing high cholesterol, which is a risk factor for heart disease.
Both type 2 diabetes and high cholesterol can often be managed by diet and lifestyle changes. Traditionally, a high carbohydrate and low fat diet with healthy carb sources and fiber-rich foods was considered best for people with type 2 diabetes.
Over the past few years, some studies show that following a low carbohydrate, higher fat diet may be beneficial for those with type 2 diabetes.
A study published in January 2023 found that 51% of study participants achieved type 2 diabetes remission following a low carb diet. Research published in October 2024 reported that following a low-carbohydrate diet might improve beta-cell function in people with type 2 diabetes, making the disease easier to manage.
Now, a new study recently published in The American Journal of Clinical Nutrition adds to this body of research, stating that replacing a portion of dietary carbohydrates with protein and fat in the diet of people with type 2 diabetes may help improve their cholesterol levels.
This new research consists of findings from two different studies completed at Copenhagen University Hospital Bispebjerg in Denmark.
The first Isoenergetic (Iso) study included 30 participants with type 2 diabetes focused on maintaining their current weight, while the second Hypoenergetic (Hypo) Study consisted of 72 participants with type 2 diabetes aimed at losing weight.
For both studies, participants were provided with all meals for either a carbohydrate-reduced high-protein (CRHP) diet or a conventional diabetes diet over a six-week period.
The macronutrient breakdowns were:
- carbohydrate-reduced high protein diet: 30% of calories from carbohydrates, 30% from protein, and 40% from fats
- conventional diabetes diet: 50% of calories from carbohydrates, 17% from protein, and 33% from fats
When analyzing the Hypo Study, weight loss caused by following the CRHP diet tended to reduce TRL and LDL levels and increase HDL, compared to those who lost the same amount of weight following the conventional diabetes diet.
However, in the Hypo Study, the metabolic effects of the CRHP diet compared to the conventional diabetes diet were less noticeable. The researchers suggest that this is because the weight loss in both diet groups effectively improved cholesterol and lipoprotein levels, likely outweighing the impact of macronutrient differences in the diets.
In both studies, researchers also found that following the CRHP diet was linked to decreased
Medical News Today spoke with Yu-Ming Ni, MD, a board certified cardiologist and lipidologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA about this study.
“Usually low carbohydrate diets come with higher fat intake (and) that higher fat and cholesterol intake tends to lead to higher levels of cholesterol, so this finding would be a little bit unusual. I’d like to see it replicated in larger studies, but whether that actually leads to a reduction in cardiovascular disease is debatable, because we do know that generally higher carbohydrate, lower fat diets such as the Mediterranean diet tend to be a little bit more healthy and have lower rates of cardiovascular disease. My first reaction is definitely interesting and probably needs follow-up.”
— Yu-Ming Ni, MD
“We know that patients with type 2 diabetes have higher risk for cardiovascular disease, regardless of the cholesterol levels, because the glucose in the blood can damage the lining of the blood vessels — we call it vascular injury,” he continued. “And when the blood vessels get injured, there is a higher chance for inflammation of the area, for cholesterol plaque to form in that area, and to result in a heart attack or a stroke from that.”
“It’s always important to do research on dietary patterns because what you eat is exceptionally important for your health,” Ni said.
“You would think that for something as important that we do every single day of our lives, multiple times a day, that we’d have clarity on what sort of a healthy diet to pursue, but there are actually still some questions outstanding, just because of challenges in doing research in this area. So any research studies that help us to determine what exactly is considered the best heart-healthy diet are appreciated,” he added.
MNT also spoke with Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight to get her top tips on the best carbohydrates for readers who have type 2 diabetes or are prediabetic.
“Often the first-line of addressing glucose control when working with those who have prediabetes or diabetes is adjusting carbohydrate intake as well as educating about why it matters (hint, carbohydrates break down to glucose which in turn affects blood glucose regulation), the quality, the variation among carbohydrate food groups (the carbohydrate profile of a donut is much different than the amount of carbohydrate in broccoli, or even a potato), and all the nuances in between,” Richard explained.
“Cutting out carbs completely typically is not beneficial in the long-term either. We need carbohydrates for fuel, for brain health, for fiber, for numerous reasons. However, it is about the type, the amount, and the quality of carbohydrates needed alongside protein and fat per individual that can make a significant difference.”
— Monique Richard, MS, RDN, LDN
Richard suggested concentrating on foods with naturally low carbohydrates that are often higher in fiber has proved to be beneficial, such as:
- leafy greens
- tomatoes
- carrots
- onions
- cabbage
- cucumbers
- bell peppers
- celery
- cauliflower
- broccoli
Richard also advised keeping in mind when eating higher carbohydrate rich foods such as:
- potatoes (sweet, russet, or other) to eat with the skin (after washed) for added fiber, use alternative toppings aside from butter, cheese, and bacon — maybe try mustard, herbs like chives or parsley, spices, or barbecue sauce
- using spaghetti squash, cauliflower, or shirataki noodles in lieu of pasta will significantly decrease carbohydrates and add additional nutrients of benefit
“When educating my clients and patients on carbohydrates I let them know that ‘nothing is off the table’ (pun intended). It is all about understanding portion sizes as well as how that food acts in your body. One individual with diabetes may have a very different blood glucose reaction from pizza compared to another individual with diabetes,” Richard said.
“Understanding that information with a continuous glucose monitor (CGM) as well as all the factors that may affect you as an individual (genetics, activity, current health, weight, hydration status, etc.) are necessary to figure out what macronutrient distribution will be beneficial and then understanding how that translates to meals and snacks. It can be very overwhelming for many individuals but as a registered dietitian nutritionist (RDN) I am here to support you, guide you, and assist you in navigating the path,” Richard added
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