TRUST ME I’M A … DOCTOR … A CELEBRITY… AN INDEPENDENT NUTRITIONIST … A PERSONAL TRAINER …
With so many “experts” on food, diet and health grabbing the headlines and twittersphere with their dictats, reveals and PJs (personal journeys), it’s no wonder there’s a whole world of confused consumers wondering what to put into their shopping baskets and into their mouths.
Some health professionals are also confused – they have to discard the old nutrition’s dietary dogmas that they learned at college, took to heart and have been preaching for decades and take on board the latest advances in nutrition science based on high quality evidence from randomised controlled trials (RCTs) and epidemiological studies published in leading peer-reviewed journals.
For our eleventh birthday issue, we asked Prof Jennie Brand-Miller to summarise how the nutrition landscape has changed in the past twenty years and to set out what she sees as some of the key “new nutrition” lessons for health and wellbeing we have learned that will help us achieve and maintain a healthy weight and reduce our risk of chronic disease.
The “new nutrition”: Jennie Brand-Miller’s six key lessons
Lesson 1. There are lots of ways to skin a cat. And there are lots of healthy eating patterns that can add years to our life and life to our years. Higher fat-Mediterranean diets, traditional higher carbohydrate Asian diets (rich in rice and vegetables), higher protein diets and low GI diets can all be accommodated and give people plenty of choice. This approach also takes into account the diversity of our cultural and ethnic backgrounds and at the individual level, it is more sustainable over the longer term.
Lesson 2. The low fat strategy failed. The findings of large, long-term randomized controlled trials (RCTs) have shown that it did not have the desired outcome. It did not prevent people from getting heart disease, stroke, type 2 diabetes, breast cancer, and colorectal (bowel) cancer etc. In fact, the prevalence of obesity and type 2 diabetes just continued to increase. It is consistently associated with weight re-gain. It does not reduce the risk of chronic disease.
Lesson 3. We need to pay more attention to protein sources (whether it’s beef, pork, lamb, poultry, dairy, eggs, seafood or plant protein) because protein is the most satiating of the three macronutrients. The quality of those sources is important for our health and for the planet. All of them can be prepared in healthy or unhealthy ways.
Lesson 4. We need to pay much more attention to carbohydrate quality – both the good everyday carbs and the traditional staples made from them and the occasional treats. What we discovered was that some carbs were worse for us than saturated fat – carbs with high glycemic index (GI) values, in particular, were linked to higher risk of cardiovascular disease, type 2 diabetes and some cancers. We also found that eating healthy low GI carbs is a short cut to a healthy diet.
Lesson 5. Head to head in high quality RCTs, we found that:
- • Energy-dense, high protein-very low carb diets were associated with faster weight loss and better cardiovascular disease risk factors than low fat diets.
- • Higher fat, Mediterranean style diets produced better weight control and cardiovascular outcomes than low fat diets.
- • Low GI/low glycemic load diets were associated with improved diabetes control, prevention of weight re-gain and reduced risk of type 2 diabetes.
These alternate diets share an underlying, unifying mechanism:
- • They reduce postprandial glycemia and insulinemia.
- • They reduce oxidative stress and inflammatory markers, not just (bad) LDL-cholesterol and triglycerides.
- • They rely on the naturally satiating qualities of individual foods to control appetite, not on counting calories or grams of fat or carbs.
- • They focus on real foods rather than macronutrients.
Lesson 6. Appetite matters. Appetite is what drives our energy intake. It is not possible to balance energy intake and energy expenditure by counting calories because:
- • Firstly, no one knows how many calories they expend each day. Even if you could, the calories (kilojoules) on food labels are not precise enough – they are at best good guesses.
- • Secondly, mathematical modelling shows that a small but persistent excess of only 7 calories (30 kilojoules) per day over and above energy requirements for 10 years underlies the current epidemic of obesity.
The best way to balance calories in and calories out is to weigh yourself regularly (on accurate scales), say monthly, or use the belt test.