Fat vs Carbs — is the debate finally over?

Magnified illustration with the word Weight Loss on white background.

Dietitian Kelly Pelham studies the results of a major new clinical trial focusing on low-fat/low-carb diets . . . .

How often do you reach into the butter dish and lick your fingers clean of buttery goodness? Or how about chewing down slice after slice of plain, white bread? For the majority, you probably answered “not often”.

You see, the problem is not fat alone, nor is it carbohydrates. It’s the combination of the two, such as spreading butter thick as cheese on white bread.

Nevertheless extremists still don’t get it, with current hype around high-fat low carb diets. They continue to push and push their nonsensical dietary claims, making a lot of money from the accepting public.

However, tables are turning with a major new randomised clinical trial recently publishing their results; concluding neither low-fat or low-carb is better than the other for weight loss.

The DIETFITS studyFor 12 months, 609 participants were assigned to either a low-fat or low-carb diet. On average, they were 40 years old, had a BMI of 33 (classified as obese), and free of major health issues. After 12 months, 79 percent maintained their low-fat or low-carb diets.

The low-fat group achieved (on average) 5.3kg weight loss and the low-carb group 6.0kg weight loss, an insignificant difference. Interestingly, this study also concluded someone’s genes or insulin production did not influence whether a low-fat or low-carb diet was better for weight loss. What’s great about this study is researchers were able to overcome barriers seen in many weight-loss studies such as recruiting a large number of people for a long period of time.

Plus, they carefully monitored compliance by measuring blood lipid changes and whether someone was primarily burning fat or carbs for energy. Over all, they found no significant differences in weight loss and many other health markers between the two groups.

How low was low?Initially the low-fat and low-carb group ate only 20g of fat and carbs each day. However, the researchers knew this was not realistic (or healthy) long term. After two months participants added back fat or carbs to what they felt was the lowest intake they could maintain.

In the end the low fat group were eating on average 57g fat per day and the low-carb group 132g carbohydrates per day.

These intakes are not what ‘extremists’ would like to see with some low-carb/ketosis advocates claiming you must be under 50g carbs per day.

The main point to take away here . . . they were still allowed fat or carbs. Instead of prescriptive intakes participants reduced their respective nutrient to the lowest amount they believed achievable, which on average was still low.

What else was special about this study?It was not just about fat vs carbs. Diet quality was seen just as important. Vegetables, whole-foods and home cooking were encouraged while added sugars, refined carbs and trans fats discouraged.

Improvements were seen in the types of fat and carbohydrate food chosen, indicating participants were making overall better food and drink choices.

More importantly, the most successful participants indicated their relationship with food changed. Once again you are seeing support for mindful eating when it comes to weight loss.

Worthy to note, participants also had 22 sessions with a registered dietitian. Not only does this highlight the importance of choosing a real expert to help you with weight loss, but you can’t expect a quick fix in one session.

Finding the balanceSuccessful participants reduced their overall calorie intake and maintained this, whether it was by reducing fat or carbs.

They did not feel deprived because they were not limiting food to an extreme extent. Your body needs both carbohydrates and fat to function optimally. Yes, it can adapt if need be but what are you missing out on? Are you compromising bowel health, your gut bacteria, energy levels and sleep by cutting carbs? Or your body’s ability to produce hormones, absorb fat-soluble vitamins, regulate body temperature, produce energy, and maintain brain and nerve function by cutting fat?

At the end of the day, going low-fat or low-carb is not the answer. It’s about finding a healthy eating style you are going to be happy to follow for the rest of your life.

Kelly Pelham is a New Zealand-registered dietitian and sports nutrition educator. As a fanatical foodie with a passion for health and nutrition, dietetics was the perfect path, she says. Based at Three Rivers Medical, Kelly is committed to helping people accomplish their nutrition, health or sporting goals.