Why diets work

There are many diets out there, some of which you may have tried. But the fact that there are so many and they’re so apparently ‘different’, means there isn’t a one-size-fits-all when it comes to controlling your weight.

But are they really that different? How can they work if they all use different methods? Well, I’ll let you into a little secret with some examples of popular diets:

  • The 5:2 Diet = Creating a kcal deficit by restricting kcal intake on two days
  • Intermittent Fasting = Creating a kcal deficit by eating later in the day, meaning meals are closer together so you’re less likely to snack and can eat smaller portions.
  • Low Carb High Fat/Keto = Creating a kcal deficit by restricting an entire food group. Since most snack foods contain carbs, it’s hard to overeat because you’re simply limited on what you can eat. Anyone ever binged out on avocado?
  • “No carbs in the evening” = Creating a kcal deficit by limiting an entire food group for 30% of your intake and usually largest meal of the day
  • Weight Watchers = Creating a kcal deficit by assigning a points system to all foods and limiting your number of ‘points’ (kcal) you are allowed to eat.
  • The Zone = Creating a kcal deficit but changing your macronutrient intake to sate appetite and energy levels, usually by reducing carbs. It’s also difficult to overeat snack foods and stick to the ratios. Since most bad foods are low in protein.
  • Paleo Diet = Creating a kcal deficit by limiting your intake to a very narrow food group, cutting out all processed food, which isn’t bad, in fact it’s great. But it also cuts out foods that are wonderful for you. Also, it’s pretty tough to get fat on meats, fish nuts and berries.
  • Raw Food Diet = Creating a kcal deficit by limiting foods to raw; i.e. no chocolate, crisps, pizza, burgers, basically all foods that are easy to over consume. Binge on raw potato anyone?
  • Meal Replacement Shakes = Creating a kcal deficit by replacing entire meals with ultra-low kcal liquid intake that just about covers micronutrient intake, but ultimately just means you’re eating a lot less kcal per day.

Did you spot what they all have in common? While they all use different methods, and have separate claims as to why they are so good for you, ultimately the single biggest reason any of them work in assisting weight loss is because they create a negative energy balance, or kcal deficit.  You will only make significant changes to your weight, be it increase or decrease by manipulating the energy balance between what you consume and what you use.

Want proof? Sure, try any of these diets eating a 1000 kcal per day surplus and you’ll pack on weight no matter how well you eat, because excess energy from food intake will be converted to fat stores. It’s not the diet, it’s the kcal intake.

That’s not to say that any of these diets don’t have some health benefits other than weight control. The zone diet encourages people to think about their macronutrient ratios, ensuring you’re balancing protein, fats and carbohydrate to provide you with the nutrients you need to be healthy and function correctly. The Paleo diet promotes natural foods that are more recognisable to our bodies in place of processed foods, however it does restrict some perfectly healthy foods just because we farm them, i.e. potatoes, grains etc. Fasting diets can help people function better from natural energy reserves in the body, and they also teach people how well they can function even if they’re not eating first thing in the morning. It also can help reduce cravings since you gain discipline from fasting and when you do eat, your meals are closer together, so you don’t feel as hungry in between.

If following a set of rules or a strict protocol works for you, that’s great. What many of these diets do is provide structure that people can follow, a clear set of guidelines so that they can lose weight, and hopefully eat healthy foods. And if that’s what it takes to get someone to be a healthier bodyweight, and eat better food, then that’s also brilliant. However, let’s please not lose sight of why they may lead to weight loss. There’s no secret, other than they simply make you eat less calories than you were, and as such you lose weight.

Perhaps my one question to people that try these types of diets, now that they know it’s simply a case of energy balancing, why not just eat a balanced diet all the time? Allowing some flexibility but accounting for it elsewhere in your diet. If you’ve got the discipline to cut out carbs for example, which can be very socially limiting too, why not just use that discipline to eat great foods within a sensible kcal intake and allow yourself some treats in moderation?

Let’s use the 5:2 as an example; 2000 kcal per day for 5 days, then 500 kcal per day for two (fasting days are not meant to be back to back). Over the week you create a 3000 kcal deficit. Why not just have 1500 kcal for 6 days and then one treat day of 2000 kcal? It adds up to the same intake.

If you focus on eating better quality foods with higher nutrients, foods rich in vitamins and minerals, cooked better and eaten in sensible portion sizes you’ll feel and perform optimally and control your weight. If we eat quality foods, we can get everything we need from fewer kcal, which means we can have a little wiggle room for those slightly naughty foods.

One popular method would be to look at the 80:20 ratio when it comes to good and bad foods. If 80% if your energy intake comes from nutrient rich foods, with plenty of protein, essential fats, carbohydrates, vitamins and minerals then you can let the other 20 % come from ‘treat’ foods. As long as you’re operating in a kcal balance or deficit, if you’re trying to lose weight then you’ll maintain or reach your goal.

Sounds pretty simple, almost too simple, right? Well, yes but the reason no one’s written a best-seller book about ‘moderation’ is because it’s very hard to market and make money on moderation. It’s not sexy enough, or controversial to make people want to do it. Fads are called fads for a reason.

Coach Phil

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