The third week of January, and the guilt is starting to set in... why can't I stick to my New Year's resolutions?
The simple answer: Because you're human...
But don't despair. Thanks to the very latest research on losing weight - and keeping it off - we now, at last, have some simple, effective rules which should work for everybody, all the time.
So here comes the science... the best, most modern recommendations for getting in shape, and staying that way...
1: Don't skip meals
Scientists studying the effects of hunger on the brain have found that subjects who miss meals suffer cravings for high calorie, high fat food. Hunger, it seems, encourages the brain to guide us towards calorie laden food - that's why you scoff pastries mid-morning...
2: Eat a good breakfast
Eating a protein rich breakfast - eggs and fish in particular - keeps you satisfied for longer, because it triggers the release of chemicals that tell the brain you are full.
3: Eat off smaller plates
It sounds ridiculous, but it works. Using smaller plates automatically encourages us all to eat smaller portions. And, no matter what mammy told you, you don't have to clear your plate!
4: Don't cheat on the calories
If you're going to count calories, do it properly. Keep a food diary, and record EVERYTHING you eat, including every snack and calorie laden sauce. You'll be surprised at how much you snack, and you can start to weed out the sneaky calories. People generally under-report their intake by 40 to 60%.
5: Eat more soup
Soup fills you up for longer. In a recent BBC study, two groups of soldiers were served the same lunch - chicken, rice and vegetables with a glass of water. One group, however, ate the solid food, while the other soldiers had their food liquidised and served as a soup. Ultrasound scans showed the soup stayed in the stomach longer, and kept the souped-up soldiers feeling full.
6: Minimise choice
Our bodies are hardwired by evolution to seek out variety in food. It's in our nature to want lots of different things. So keep away from the buffet - where you're likely to eat as much as 30% more. And only buy what you need. Studies show that when people are offered two bowls of free sweets - one bowl all purple, the other multi-coloured - that they tend strongly to pick the multi-coloured sweets, and eat much more of them.
7: Enjoy low fat dairy products
Eating low-fat dairy products helps the body to excrete more fat. Dairy calcium binds with fat in the small intestine and then passes through without being absorbed and stored as fat. Skimmed milk, low-fat yoghurt, cottage cheese and fromage frais all help to carry fat away from the gut.
8: Feel The Burn
Exercise. The calorie 'burn' from exercise doesn't stop when you get off the treadmill, the pitch or the bike - it carries on well into the next day. In fact, you'll burn more calories in the hours after you exercise than you will during the exercise itself. That's because the human body accesses carbohydrates easily during exercise, but has to use stored body fat to run itself in the following hours.
Run, walk, dance - just move your body, in any way you can. Even little bursts of exercise - taking the stairs, getting off the bus a stop early, walking around as you use the phone - it all adds up. Building small amounts of 'activity' into daily routine increases heart rate and calorie expenditure.
Colette O'Flynn is the chief physiotherapist at PhysioNow