August 23, 2012

Are Low Fat Foods Making Us Fat?

Hey kids, it's Crabby!  Who is once again not posting while on vacation. So yes, this is a guest post, as you can tell by the fact that there is actual nutrition research involved. If I'd written it, there'd just be a bit of nagging about not trusting slick advertising campaigns, followed by some whining about the lack of healthy convenience foods for lazy people, and then perhaps some gratuitous pictures swiped from icanhascheezburger.

(Photo credit:

Whoops, sorry--not sure how THAT got in there!

So thank goodness this post is by Brendan Wilde, who is a health and wellbeing writer over at and the UK National Register of Personal Trainers (where you can learn more about personal trainer courses if you're so inclined). While he does the hard work of explaining the metabolic implications of various dietary variables and particularly the impact on insulin resistance and weight gain, the Crab and Lobster will be kicking back enjoying their final days in Scotland.  Which, as it turns out, has a more incredible scenery than any human can absorb without exploding, plus many delightful ways to screw up your metabolism six ways from Sunday.  Um, unless beer and shortbread cookies have been declared health foods in my absence?

Anyway, I'll shut up now.  Take it away, Brendan! 

Is the low fat food fad all it is cracked up to be?

Do reduced-fat foods help us lose weight? Or could they actually be contributing the rise in obesity?

Processed foods may well be low in fat, but we all know that does not mean they are low in calories.

In fact many low fat foods have just as many calories as their full fat counterparts. And furthermore, many low fat foods are ‘adulterated’ with additional, high glycaemic carbohydrates, to improve the taste. Especially popular and troublesome is the controversial sweetener high fructose corn syrup.

The importance of Dietary Fats for General Health

Dietary fats are essential to our overall health and wellbeing. They help us absorb fat soluble vitamins A, E and K; they serve as a reservoir for energy storage; and they are needed for the healthy function of our brain, nervous, immune and hormonal systems.

They are also essential for helping maintain a normal metabolism which controls how quickly our body burns energy. Severely limiting fat intake will slow down our metabolic rate, meaning we need fewer calories initially, but also meaning that we gain weight quickly as soon as extra calories are added.

Fat, Insulin and blood sugar

Then we need to add the hormone insulin into the equation, which has everything to do with fat storage and weight-gain. Insulin is the hormone responsible for regulating our sugar levels by moving sugar out of the bloodstream and into our cells. The body first converts this sugar into glycogen, which is stored in the liver and muscles. When they are full, the remaining glucose is stored as body fat.

However, it is vitally important to understand that insulin – and subsequent fat storage – behaves differently, depending on the types of food eaten. Carbohydrates especially are high-GI carbs such as the sweeteners added to many low-fat foods, stimulated the greatest insulin response. Fats, on the other hand, do not raise insulin or blood glucose levels.

When insulin is circulating in the bloodstream, even at quite low levels, fatty acid synthesis is activated, and the burning of stored fat is greatly inhibited. Insulin prevents your body from making the hormone-sensitive fat-burning enzyme, lipase. Essentially, this means that your fat-reduced processed foods, with added carbohydrates, force your body into making fats, not burning them!

When you eat a low-fat, high-carb food, your blood glucose level will be back down to normal after about 90 minutes, but your insulin levels will still be high, working to stack glucose away in your fat cells. This often leads to a blood sugar slump, which comes with an overwhelming desire to reach for the next carbohydrate fix… often in the shape of a chocolate biscuit or a slice of cake. And so the whole cycle begins again. Hunger is ever-present and along with it comes gradual weight gain.

Repeated for long enough, this cycle of insulin elevation can lead to insulin resistance, whereby ever higher levels of insulin are needed to move blood sugar across the cell membranes, More insulin means more fat deposition, and this is a precursor to the development of Type ll diabetes.

Ironically, the most comfortable and effective way to lower insulin levels, and encourage the body to burn stored fat instead of blood glucose, is to limit carbohydrates, while making sure that you are taking in adequate levels of healthy dietary fats.

This forces the body to burn fat for fuel, without any of the feelings of starvation inherent in low-fat, low calorie dieting.

So, how do you regulate insulin levels and encourage your body to burn fat? Not by becoming a low-fat junkie! Exercise regularly, using a combination of aerobic activity and resistance training to build lean muscle, in order to increase your resting metabolic rate. Eat five or six mini-meals a day, made up of low-glycaemic index carbohydrates (vegetables or fruit), healthy fats and proteins. And avoid the high glycaemic index carbohydrates frequently found in processed food as a result of added sweeteners such as high fructose corn syrup.

What do you folks think about "low fat" foods, do you grab 'em up or take a more skeptical approach?


  1. I used to grab them and now I don't. I tend to buy full fat foods that are as close to nature as intended and just account for the extra calories/fat in my diet as long as I stay within my macros I'm good.

  2. Thankfully the low fat crave tasted so bad (I wish I could remember the company name that made all the terrible tasting cookies) when I first remember the big push that I wasn't remotely interested.

    Nope, love my fats. As a vegan this is going to be the nuts, avocados, nut butters. And yes, you (I) can overdo them. So I have to be careful. I still feel better eating them however.

  3. The "low fat diet" is an experiment on human health, begun by the FDA with no research to back it up, and it has proved that they got it wrong.

    Whole, real foods, that grew out of the ground, should make up the vast majority of our diet.

  4. I used to fall that the low fat stuff - way back when the Snackwells hit the market! :-) Whole foods for me now - I learned my lesson! I was young then! :-)

  5. Way back when...I used to eat low fat. I couldn't lose weight. I was starving all the time. Now, I avoid low fat foods at all costs.

  6. I too fell for the whole low-fat thing back in the 80's when all the experts were telling us to count grams of fat. It wasn't our fault! Love that avocados, salmon, nuts etc are now A-OK. But I'm still confused about saturated fats, what with the paleo people saying Go For It, and most mainstream dietary experts saying stay the hell away. Sigh.

    Thanks everyone for stopping by, and I'll be back soon for realz!

  7. I put weight on partly by eating Fry's turkish delight bars with my lunch - only 8% fat you know. Shame about the sugar.

    Low fat branded diet foods tend to replace the fat with sugar I discovered. Not necessarily a good idea. And some of them still manage to taste like cardboard.

    I did manage to lose weight on a low fat diet but I'm finding that taking some low carb principles on board seems to be better for maintenance.

    I've been reading quite a bit of paleo stuff and although I don't think the full works is for me, I have been eating more fat recently. I find a protein and fat based breakfast keeps me full up till lunch, which cereal, toast and fruit never does.

  8. I think I do alright in the fats department, I just overdo in the bad carbs department (I love my breads). Now, I just have to figure out what good carbs are and stick to them.

  9. When people see something that is "low fat" they think that means that they can eat more. What happens is that they end up eating more than they should have and consume too many calories.

  10. I've always been skeptical about "low fat" food, they're overrated and do more harm than good in some cases really.

    Elwood Gym, Melbourne Yoga, Melbourne Pilates

  11. The National Weight Control Registry monitors people who have lost weight then kept it off. They say that the majority of the people they monitor have a low fat high carbohydrate diet. These are people who have to deal with the "former fat person's reduction in metabolism, compared with a never fat person", yet are successful in maintaining. So, given that, I don't believe that "low fat foods are making us fat". What is making us fat is overeating. Too many inexpensive, yummy foods, in an environment where the majority of people are already overweight. It doesn't matter whether we overeat fat or carbs (personally I could never have a protein binge).

  12. Anything in excess is added fat. If you think about it, 0% is a round off for 0.01 of something...consume too many and it adds to a whole lot of figure. Controlling how much you eat and how much you consume daily, may help in figuring out how much you need to burn. If you take in this much then make sure to burn just as much or even more to maintain your weight.

  13. ahhh it all makes me think of SUSAN POWDER and my beloved SNACKWELLS :-)

  14. That was very informative and I couldn't agree with that more. Indeed people in general equates low fat food with loosing weight, which may not always be the case since there are still a lot of factors involve, such as the calorie count. In my opinion, the best way is by reducing portion sizes and paying attention to the amount of calories that we intake.

  15. I agree whole heartedly that eating clean is the real solution! Not foods labeled as "low fat" or "low calorie" that often encourage society to over indulge as it's 'better for you.' I worked for 2 years as a Preschool Teacher before I began working FT from home and those kids knew MORE about Nuggets than they did fruits or vegetables! It was MY JOB to teach them about the foods on their lunch plates and how it helped their bodies. Nutrition education starts at HOME and it's really up to US to teach the next generation that food doesn't come from a box or bag in the freezer section & a microwave is NOT the only cooking appliance needed.

  16. I think it's not but what makes us fat is the sweetener high fructose corn syrup. If the low fat foods you're buying has fructose, it means that it is really not a low fat foods. If you will read most articles about fructose you'll see lots of health experts telling that fructose can cause obesity and can lead to lots of health problems.

  17. In his book "Eat to Live" (which Crabby reviewed, Dr. Furhman makes a good analogy about "low fat" foods. Take a glass of with 98 tablespoons of water in it. Add 2 tablespoons of melted butter. The result is 98% fat free, but 100% of the calories come from the butter. Its not necessarily the fat % of the food you are eating, but the source of the calories.

  18. I agree with you. It doesn't mean that we are eating low fat foods, we are now have a higher change not to gain fats or weight, it still depends. Most of the foods nowadays are processed and as much as possible, we should minimize the usage of it for health reasons. The best thing to say is, to avoid gaining weight or if we want to lose weight we should avoid fatty foods and also we should do regular exercise.

  19. Buying low fat foods can only make your pockets empty and cannot guarantee you that you can trim down those fats. Still, the best way for me is to eat more greens and exercise daily, surely you can expect better results!


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