EAT FOR HEALTH Australian Dietary Guidelines

EAT FOR HEALTH – AusTRALiAn diETARy guidELinEs

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Guideline 1

1.3 How dietary patterns can affect energy balance and weight outcomes

Environmental and lifestyle factors resulting in overconsumption of energy in the diet and a decrease in physical

activity are major contributors to the obesity epidemic. A small, persistent energy imbalance is enough to

cause excess weight gain in both children and adults, which over time progressively increases the BMI.135,139

Available data from developed countries, including Australia, confirm an increase in energy intake concurrent

with the dramatic increase in the prevalence of overweight and obesity in children and adults since 1980.^139

There has been much debate about the role of energy, carbohydrate and fat intake in the obesity epidemic.236,259,260

While reducing excess fat intake has been recognised as an important strategy to reduce energy intake in successful

weight loss interventions,^259 there is little evidence that population fat intake is associated with the obesity epidemic

independently of total energy intake.^260

Foods with a higher energy density encourage energy intake above requirements.198,261 Foods that are high in

energy density also tend to be more palatable, and high palatability is associated with increased food intake in

single-meal studies.142,262 Fat and sugar are positively associated with energy density while water and dietary

fibre are negatively associated. Fat plays a role because of its high energy density compared to protein and

carbohydrates. Water and dietary fibre play a role through a dilution effect, although this is less for dietary fibre

because of the much smaller range of fibre concentrations in food compared with both water and fat.

It is plausible that the proportions of macronutrients (fat, carbohydrate, protein and alcohol) and types of

macronutrients comprising total energy intake may affect an individual’s propensity to habitually overconsume.

In this regard, dietary patterns that tend to be relatively low in total fat and moderate (not high) in carbohydrate

are consistent with reduced risk of excess weight gain. Energy from drinks, in particular, may add to total energy

intake without displacing energy consumed in the form of solid food, and it is plausible that sugar-sweetened

drinks may contribute to excess energy intake through lack of impact on satiety.^216 The satiety value of foods may

also be important in managing appetite and hunger.^263

Energy-dense dietary patterns are associated with higher consumption of grain-based foods, fats and sweets

and lower consumption of vegetables and fruit.^264 International data suggest that the major foods contributing to

increased energy intake include sweetened drinks, snack foods and fast food261,265,266 and that increasing portion

size is also an important contributor.198,267,268 The low cost of energy-dense nutrient-poor food relative to nutrient-

dense food also has a major role.261,264

The three key lifestyle areas related to overweight and obesity are dietary pattern, physical activity and behavioural

change. Multicomponent interventions that address all three areas are more effective than those that address

only one or two. Positive outcomes have been described, at least in the short term, in clinical weight loss

regimes that include a range of interventions.269,270 For further information, see the NHMRC Overweight and

Obesity Guidelines.^121

1.4 Practical considerations: achieve and maintain a healthy weight

Intentional weight loss in overweight and obese individuals reduces the risk factors for mortality and morbidity,

and alleviates the symptoms of many chronic conditions.269,270 It is not necessary to lose large amounts of weight

to achieve substantial health gains. For example, it is estimated that a weight loss of 5 kg in all people who are

overweight or obese would reduce the national prevalence of type 2 diabetes by 15%.^271 Improving nutrition

and/or increasing physical activity also benefits health in areas beyond weight control, such as bone strength,

mental health and immune function.2,272

There is a need to provide population guidance on promotion of healthy weight, primary prevention of overweight

and obesity, weight maintenance, weight loss, and management of weight-related conditions, disorders and

diseases. A focus on healthy weight is a more positive way to address weight issues than focusing on obesity

and overweight. It encourages those who are a healthy weight to maintain that weight. It also helps to reduce

the risk of any unintended negative consequences, such as disordered eating. Promotion of healthy weight

incorporates prevention and management of underweight, overweight and obesity in children and adults and

promotes healthy growth in children.