I would also suggest people in this thread look into picking up some digestive enzymes once you reach your goal weight. Being over-weight and obese can completely destroy many of the enzymes and other bacteria beneficial for digestion. Meaning it becomes harder to absorb your food, and takes longer to fully digest each meal. You only need to take them for 4-8 weeks and it should replenish and repair any damage that was done.
In terms of Fish oils, they are great, but don't do much unless you take a pretty good brand. Always look for high EPA and DHA levels in your fish oils. Those essential fatty acids are what makes taking Fish Oil good for you. Without them, or with low levels, it really doesn't do much at all. I personally take Now Super Omega EPA. it contains 750mg of EPA and 540 MG of DHA per two softgels, I take four per day, two in the morning, two in the afternoon.
A good multi-vitamin can also go a long way to helping your body during weight loss. Both in providing vitamins and minerals you need to keep bodily functions continuing, and helping to repair damage a neglectful diet can lead to.
Calcium - Don't forget calcium. Many people jump on Ketogenic or low-carb diets and eat only meat and eggs. Some eat cheese maybe once a day. Many people don't realize they are neglecting Calcium, which is extremely important. If you do buy a Calcium product, and are taking a multi-vitamin, make sure your calcium supplement does not continue huge amounts of Vitamin D3 or Zinc. Both can become problems in abundance. For example, my multi-vitamin provides 1,000 IU of Vitamin D3 per day, and 15 MG of Zinc. Both 100 or more percent of your daily intake. Most calcium products also include these in high amounts. Meaning I could potentially be getting to much. Zinc, for example, is fantastic for the male body, but in amounts of 100mg or more, could cause many health problems, and some studies even link it to prostate cancer. Be mindful of all these things.
There are a number of really good supplement companies on the market, providing top quality products. You need to buy supplements from good companies because they will make sure only the purest forms of what they are selling are used. I personally only use Optimum Nutrition, and Now products. Only will I stray from them if they do not produce what I am looking for, or if I am reaching for a certain goal and need something tailored to me (like Animal Pak's etc..).
