Does eating less help you to lose weight?
Posted by kathryn in Uncategorized
The final question in this month’s Q & A Thursday is on the topic of weight loss:
Is it possible to gain or not lose weight when you restrict your calorie intake? Is there an optimum amount of food to eat for your body to burn fat?
When you’re trying to lose weight it’s tempting to take the less is more approach – the less food you eat, the more weight you’ll lose.
But this is not necessarily true. And being in a hurry to lose weight can be detrimental – slowing down and even stalling your weight loss.
Your metabolism
One of the keys to losing weight is your metabolism. All day the cells in your body are doing stuff. They’re repairing, building muscle tissue, making hormones, breaking down by products, keeping your immune system on track. They’re very busy keeping you alive and well.
All of these metabolic processes are fuelled by food. As food is broken down by your digestive system it provides the energy which powers these activities.
Energy in vs energy out
The basic weight loss equation is all about energy: the energy going into your body, from the food you eat vs the energy you expend, through living and exercising.
If the energy you consume is less than then energy you expend, you will lose weight.
One of the tricks of weight loss is to maintain and even boost, your metabolism. Increasing your metabolism will increase the energy you expend. Tipping the weight loss equation in the right direction. Keeping a strong metabolism will encourage your body to make use of its fat stores – enabling you to lose weight.
Extreme energy restriction
If you restrict your kilojoule intake too much, this will slow down your metabolism. And make it harder for you to lose weight.
If you are female and consuming less than 3,300 kJ per day your metabolism will decrease by about 20 percent. Your body will also start using some of its muscle mass as energy, which depletes your metabolism even further.
All of which makes it damned hard to lose weight.
Plus you’ll be feeling more tired than you should and it’s hard to maintain this level of restriction long term.
The optimal energy intake for weight loss
If you are female, for optimal weight loss you must keep your energy intake between at least 5,000kJ and 6,500kJ. At this level your metabolic rate will only decline by about 5 percent. Plus, more significantly, about 90 percent of your weight loss will be from your fat stores.
Boosting your metabolism
The other way to boost your metabolism when losing weight is to increase your exercise. This has so many benefits to your health in general, plus it speeds up your heart rate and builds muscle mass – both of which increase your metabolism. Both of which help you to lose weight.
What is Q & A Thursday?
This post is part of Q & A Thursday – a monthly burst of blogging, where you get to dictate the subject matter. Q & A Thursday is all about simple, practical answers to food and diet dilemmas sent in by readers.
If you have a question you’d like answered send me an "email":mailto:me@kathrynelliott.com.au. For more information you can take a look at the Q & A Thursday archives.
05 June, 2008
Comments
Good information about metabolism. Not eating enough will definitely slow it down. Eating good healthy foods in proper portions will help to maximize it.
I’ve definitely found that eating too little will hinder weight loss (and exercise will help it), but am I reading right? 3300 calories? Or are kJ measured differently? At 3300 calories a day, I will certainly gain weight!
Thanks David. Good food, in the right portion sizes is fundamental to weight loss.
Ricki – noooooo. Kilojoules are the metric measurement of the energy in food. And as such are quite different to a calorie. There are about 4.184 kilojoules to every calorie. So 3,300 kJ, the level at which your metabolism seriously slows down, is about 900 calories.
The consumption levels of 5,000 – 6,550kJ equate to between
1,0001,200 and 1,500 calories But of course that’s an average, exactly what I spent another blog post criticising!My apologies Kathryn (because I love this site) for the pedantry, but 5000kj is closer to 1200 calories. It’s a fairly important difference between 1000 and 1200.
Yikes did I actually say that? Gwyneth you’re exactly EXACTLY right. Thanks for pulling me up on this. There’s a huge difference between 1,000 and 1,200. Practically a whole meal! And I’m definitely NOT recommending 1,000kJ.
The advise is meant to be: consuming between 1,200 and 1,500 calories to lose weight.
That’s what comes from replying to blog comments before you’ve had breakfast. No apologies required from you. Definitely apologies required from me!
I definitely find a huge part of the struggle to lose weight is in trying to do it too quickly. Trying to slim down in time for certain events or for bathing suit season, etc…. just causes extreme dieting, which hardly works. Reducing calorie intake reasonable takes much patience and perseverance.
Fantastic post Kathryn! Really excellent way of organising all that information to be easily digested (sorry about the pun!) :)
Agreed Cookinpanda. Losing weight for an event is rarely successful long-term. Most people can make drastic changes for a few weeks. However long-term these are impossible to sustain and still have a life. So after the event, people revert to old habits and the weight goes right back on. Slow and steady, changing your habits long-term, learning how to adapt them into your life – is a much more successful and useful strategy.
Thanks Christie – pun and all!
I realize this is an old thread but would love an answer if you see this! Surely 5000-6500 kj can’t be for all diff weight females? I need to lose about 50 pounds so I am thinking I may need to eat more? But not sure? The reason I am concerned is bc I am cutting calories and not losing and when I did a triathlon and was about 60 pounds lighter- eating btwn 1100-1400 calories during training had me holding onto weight. I figured it out and ended up upping the # to 1700-2000 a day but realize I was training ALOT.
If so, is there a formula you used to arrive at that number based on average female weight, etc.? I read somewhere that you should only cut your calories to 10-15 percent below to lose optimal weight but its tough to know the exact number you should eat anyway based on exercise, etc.
Thanks very much!!!!
Liz
Liz: the 5,000 – 6.500kJ is an average amount. Based on average heights and activity level. If you’re smaller it’s better to aim for the lower end, while if you’re taller than go for the higher amount. And this is good enough advice for most people.
However, if you are exercising extensively, then that does change the energy balance equation. I’d recommend using one of the online food journals like Fitday to work out your exact energy needs.
This will give you a more accurate energy requirement given your basic metabolism, which will be based on your height, weight and basic activity level.
You can then add in your exercise, to see how that changes your own energy equation.
Excellent post! You always hear a lot of different things, so it’s good to have some real sound advice here!
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