What should you be eating?
An ideal rapid weight loss diet includes plant-based foods, low carb vegetables, salads and fruits, as well as moderate amounts of protein from meat, chicken, fish, tofu and healthy fats from nuts, seeds and various oils.
This low-carb, Mediterranean style of eating helps you feel satisfied while preventing muscle mass losses, plus it stops your metabolic rate from crashing as you successfully achieve your weight loss goals.
The key to successful long term weight loss is dieting the right way, using only wholefoods rather than synthetic meal replacements, plus enjoying what you’re eating so you’re more likely to maintain your new diet.
What type of exercise is most effective for rapid weight loss?
It is recommended to complete 30 minutes of light to moderate physical activity each day. This can be anything from walking to yoga, Pilates or a light weights session. Exercise increases hunger which can make a rapid weight loss program more challenging to adhere to. However, after transitioning into mild nutritional ketosis (after the first few days) you may feel energetic and quite keen to exercise.
It is important to listen to your body. The decrease in calories could make it difficult to participate in high intensity activity and that’s ok. When in mild nutritional ketosis, the stores of sugar in your body, which is what we normally rely on for high intensity exercise, have been used up. Instead of sugar, your body is relying on fat as an energy source.
As a result, you may experience lethargy or light-headedness when participating in training such as HIIT, F45 or Crossfit. It is recommended that you add an additional protein snack or split your snack allowances to match your training program. You may like to have half a fruit snack prior to exercise to give your body some natural sugar to run off, and then have half a protein snack afterward for muscle recovery. Having a protein snack within 30 minutes of completing exercise promotes muscle recovery and maintains muscle mass.
To assist in weight loss (and general physical and mental health), a mixture of cardio and weightlifting is key.
Cardio (walking, running, cycling, etc.) is effective for calorie burning, either via interval training or steady pace exercise (a 2017 study saw that both high intensity interval training and moderate intensity continuous training both resulted in reductions in weight, fat mass and waist circumference with no significant difference between the two types of training, however the high intensity interval training is more time-efficient).
Cardio is particularly helpful for losing visceral adipose tissue (i.e., belly fat). When the body is losing weight rapidly, particularly with cardio, muscle loss and metabolic slowdown can occur to preserve energy, referred to by the term “adaptive thermogenesis”.
Weight training can help you get that ‘toned’ look and reduce the amount of loose skin that comes with rapid weight loss. But in the end, weight loss all comes down to being in a caloric deficit. Exercise can be beneficial for keeping you in that deficit by increasing the number of calories you burn.
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Should I be looking at scales or body fat percentage?
No, a number is not a complete picture of your health. Weight measured by scales is a crude measure and doesn’t tell you anything about body composition – that is, fat mass or fat-free mass (i.e., bone and muscle).
Your body fat percentage, however, can give a general estimate of overall health - the higher the body fat percentage, the higher the risk of developing metabolic conditions such as obesity, cardiovascular disease and type 2 diabetes.
Healthy body fat percentages range from 14-27% in females and 14 to 24% in males. It’s also important to measure waist circumference, as this can be a good indicator of the amount of visceral fat stored below the abdomen, which can also indicate increased risk of these conditions. Unhealthy weight circumference is considered to be above 80 cm for women and above 94 cm for men.
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What happens when you under eat?
It’s important to recognise that undereating and malnutrition are very different to eating in a calorie deficit to promote weight loss. Malnutrition refers to deficiencies, excesses or imbalances in a person’s intake of energy and/or nutrients.
There are two types of malnutrition: undernutrition and overnutrition. People who are undernourished often have deficiencies in vitamins and minerals including iron, zinc, vitamin A and iodine. It is also possible to be overweight or obese from excessive calorie consumption but not get enough vitamins and minerals at the same time. Whereas, eating in a calorie deficit and experiencing rapid weight loss while consuming nutritionally balanced meals with adequate carbohydrates, protein, fat, vitamins and minerals can nourish your body.
We recommend undertaking a weight loss program for 2-8 weeks at a time. This is as long as you are not experiencing any side effects such as fatigue, digestive issues, disturbed sleep, faltered weight loss, etc.
However, if weight loss plateaus for more than 2 weeks consecutively, you will need to consult with your dietitian to put in place a plan for increasing your calorie intake for a few weeks. This is to ensure your body does not enter starvation mode.
- Saunders J, Smith T. Malnutrition: causes and consequences. Clin Med (Lond). 2010;10(6):624-627. doi:10.7861/clinmedicine.10-6-624
What snacks can I eat?
The purpose of snacking is to ensure your blood sugar levels don’t plummet and that you have enough energy to sustain you between meals. Making sure you’re not starving to the point of being ravenous will also prevent you from overeating at your next main meal.
Aim for a mix of protein, fibre, and healthy fat to build a nourishing snack. Some good examples include cheese (such as cheddar or cottage cheese) and wholegrain crackers, protein balls or bars, a handful of nuts, hummus and veggie sticks (e.g., capsicum, carrot, celery, etc.), sliced apple with peanut butter, savory egg muffins, or hard-boiled eggs.
What should I be cutting down on?
Limit your intake of salt, added sugar and saturated fats. This means cutting down on packaged and highly processed foods, as well as take-away and fast foods.
Excessive consumption of sugars and refined carbohydrates can spike blood sugar and insulin levels very quickly which, in the long-term, can cause insulin resistance and is a major factor in the development of different metabolic conditions such as type 2 diabetes and cardiovascular disease.
Limiting refined sugars and replacing them with high fibre, low GI foods can help improve fasting insulin and reduce risk of type 2 diabetes. High saturated fat intake may cause an increase in risk of coronary heart disease because of the increasing plasma and LDL cholesterol.
Recent studies have shown that partial replacement of saturated fatty acids with polyunsaturated fatty acids was most effective at reducing coronary heart disease incidents. Consuming a diet high in salt can lead to high blood pressure which increases your risk of stroke, heart failure, osteoporosis, stomach cancer and kidney disease.
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What else can help?
Enhanced sleep – Studies suggest eating large meals before bed can have a negative impact on your sleep. Fasting gives your digestive system a chance to recover, bringing your body back to optimal functioning and homeostasis. This can help you start the day off feeling much more refreshed and energised, with a body clock that is more synchronised.
Mental health - Anxiety is recognised as linked to a person’s sleep quality, underscoring the importance of a good night’s sleep in managing symptoms of anxiety. The ability of fasting and rapid weight loss to restore your body’s equilibrium can help to lessen anxiety. This also helps those on the diet to steer away from foods that inevitably lead to energy crashes, as these can really impact a person’s mood over time.
How can I come up with a manageable goal?
- To make sure your goals are clear and reachable, each one should be SMART:
- Specific (simple, sensible, significant)
- Measurable (meaningful, motivating)
- Achievable (agreed, attainable)
- Relevant (reasonable, realistic, resourced, results-based)
- Time bound (time-sensitive)
- Make your goal a positive statement.
- Put dates and times on your goals to make them measurable, as this can in turn motivate you further.
- Write your goals down and put them somewhere you can see them every day.
- Make your goals small so they’re achievable in the short term; if a goal is too large it can be demotivating.
- Goals should be related to performance, not outcome.
Before beginning any weight loss program please consult your GP.